Method for immunizing an avian species

ABSTRACT

The present invention relates to a method for generating a plurality of different IgY antibodies, by immunizing each of a plurality of avian organisms of the same or different species with a composition comprising a plurality of different antigens, thereby generating a plurality of different IgY antibodies.

CROSS REFERENCE TO RELATED APPLICATIONS

The application claims priority to U.S. application Ser. No. 12/299,247, entitled “Method for Immunizing an Avian Species” and filed on Jun. 4, 2009, which is hereby incorporated by reference in its entirety. All patent and non-patent references cited in this application are also hereby incorporated by reference in their entirety.

FIELD OF INVENTION

The present invention relates to a method for immunizing an avian species with a plurality of antigens and generating a library comprising a plurality of different antibodies raised in said avian species.

BACKGROUND OF INVENTION

Antibodies are widely used as therapeutic agents, diagnostic tools, research tools, and more.

Polyclonal antibodies are conventionally obtained by the time consuming method of immunizing a suitable host, usually a mammalian animal, with a composition comprising the molecule of interest as an antigen and a suitable adjuvant. Several weeks later antibodies, generated by several B cell clones, hence the term polyclonal, specific to the antigen can be harvested by bleeding the animal and collecting the serum. Polyclonal antibodies may bind different parts of the antigen although individual polyclonal antibodies may bind virtually the same parts of an antigen with different affinities.

Polyclonal antibodies are usually obtained from mammalian host animals such as rats, mice, goats, horses, sheep, rabbits, pigs and others. A large amount of experimental animals are used to generate different antibodies—one animal is used per antigen. The animal will experience discomfort associated with the immunization and in particular the bleeding procedures. It is expensive and laborious to obtain antibodies specific to a large number of different antigens, since a similar large amount of animals is required.

On one occasion however, the possibility of immunizing individual animals with more than one antigen has been discussed in connection with a semi-automated method of hybridoma generation using mice immunized with multiple antigens and a novel antigen microarray assay (Proteomics 5: 4070-4081, 2005 and WO 03089471). In this document, mice were immunized with 10 μg of 5-10 different protein antigens having sizes ranging from about 12 to about 48 kDa in order to solve the bottleneck problem in providing monoclonal antibodies to proteins encoded by the human genome. In the discussion of the scientific paper it is stated that “It is also possible that increasing the number of immunogens for each animal may ultimately lower the number of positive clones in any one fusion. Indeed, subsequent production runs within our laboratory have shown that five antigens per animal are optimal”. A major problem associated with immunizing with more than one antigen is, according to WO 03089471, immunodominance. In order to circumvent this problem, the animal was injected with several antigen boosters. Immunization with more than one antigen is not recommended, apart from perhaps in special cases involving automated procedures for generating mice monoclonal hybridoma B cell lines, in which case it is recommended to immunize with no more than 5-10 different purified protein antigens. In the patent application it is also suggested that that immunization might be carried out with up to 50 different antigens. However, no specific examples demonstrate that this approach will work with a reasonable expectation of success.

Conventionally obtained antibodies have several other drawbacks in addition to being relatively expensive and time consuming to produce. It may e.g. be difficult to obtain a sufficient response toward mammalian antigens. In general, the large degree of conservation of immunoglobulin structure, immunoglobulin receptor structures, etc. among mammals does in many cases give rise to inaccurate test results when using mammalian antibodies for e.g. detecting mammalian antigens. Also, the problems with protein A/protein G binding, interference with rheumatoid factor, and activation of mammalian complement are often encountered when using mammalian antibodies and mammalian antigens.

In The FASEB Journal 4:2528-2532, 2001 it is disclosed that by immunizing a chicken during a 20 day period with a total amount of about 30-300 μg antigen, an immune response could be detected about 2-3 weeks later. It is concluded that the egg yolk is a convenient source of polyclonal antibodies because:

-   -   the quantity of antigen needed is much lower compared to         rabbits,     -   birds produce antibodies against highly conserved mammalian         antigens,     -   the use of complete Freunds adjuvant leads to very high and long         lasting titers of yolk antibodies, starting as early as 16 days         after the first immunization,     -   the purification of antibodies is simple and quick, and a purity         of 90% is easily attained by PEG precipitation,     -   chicken are inexpensive to keep and easy to handle,     -   chicken antibodies are acid- and heat-resistant and therefore         might be orally applied to prevent or to cure intestinal         diseases of young animals or humans.

The document does not however, discuss if specific antibodies can be generated in a much faster and much more inexpensive way.

It is thus known that a number of advantages are associated with obtaining antibodies in a non-invasive way from eggs from an immunized chicken rather than collecting blood from an immunized mammal. However, the time required for generating antibodies is not dramatically reduced when using hen/chicken antibodies. And also, a large amount of birds are used to generate antibodies in cases where a large amount of different antigens are used. The available literature in this field does not provide any suggestions for providing specific antibodies in a dramatically faster and more inexpensive way.

In Handbook of Laboratory Animal Science, Second Edition, Vol 1, Jann Hau e.g. it is disclosed that “For each antigen, there is a dose called the “window of immunogenicity.” Too much or too little antigen may induce suppression, sensitization, tolerance, or other unwanted immunomodulation'. Very low doses (<1 to 5 μg) are used to induce hypersensitivity (allergy) and should be avoided in immunization of animals, particularly because booster injections may result in anaphylactic shock in the animals.”

There exists a dogma within the field of immunology that repeated immunizations with low doses of allergen may result in anaphylactic shock and that it is not possible to immunize animals with a large amount of antigens.

SUMMARY OF INVENTION

The invention as disclosed relates to a fast and inexpensive method of generating a library of antibodies each of these being specific towards a pool of antigens. The antibody library is preferably a polyclonal antibody library generated by immunization of a vertebrate animal with a pool of antigens such as an antigen library. The vertebrate animal is preferably a hen of the species Gallus gallus. The antigen library may comprise a multitude of compounds, preferably peptides that are capable of raising an immunogenic response in the host animal in combination with the carriers and adjuvants with which the antigen library is co-immunized.

Antibodies have been raised in animals for decades—using one antigen per animal. According to the present invention however, large numbers of antigen specific antibodies can surprisingly be obtained by immunizing an animal with a large number of antigens. A scientific dogma and a technical prejudice have been overcome by successfully immunizing animals with a large number of antigens.

The invention further relates to a method of isolating antigen specific antibodies from an antibody library, wherein the method comprises immobilizing the antigen, contacting the antibody library with the immobilized antigen, removing unbound antibody, and recovering antigen specific antibodies.

Normally, affinity chromatography is used for capturing antigen by means of immobilized antibodies. By reversing this principle, the possibility of isolating antigen specific antibodies from an antibody library arises. It follows that the likelihood of isolating polyclonal antibodies specific to any antigen increases with increasing number of different antigens used for immunization. As a result, a tool for providing specific polyclonal antibodies within a very short time is provided by bypassing the steps of immunization and waiting for an immune response to occur.

Finally, the present invention relates to the products resulting from the various methods.

DEFINITIONS

Adjuvant: Any substance whose admixture with an administered immunogenic determinant/antigen increases or otherwise modifies the immune response to said determinant. Immunisation of the animal may be carried out with adjuvants and/or pharmaceutical carriers. An adjuvant is any substance that enhances the immune response to an antigen with which it is mixed. The antigen may also be mixed with two or more different adjuvants prior to immunisation. Examples of commonly used adjuvants comprise: Immunostimulatory oil emulsions (for example, water-in-oil, oil-in-water, water-in-oil-in-water such as e.g. Freund's incomplete adjuvant such as Montainde®, Specol, mineral salts such e.g. as Al(OH)₃, AIPO₄, microbial products, Saponins such as Qual A, synthetic products, as well as adjuvant formulations, and immune stimulatory complexes (ISCOMs). A list of other commonly used adjuvants is disclosed on pages 6-8 in WO 03089471, the list being hereby incorporated by reference. The most preferred adjuvant according to the present invention is Specol since a fast immune response is initiated. Normally, antibodies can be harvested three to six weeks after immunisation in e.g. hen, but when using Specol as an adjuvant, antibodies may be harvested after only about two weeks. Adjuvants are generally included in the immunogenic compositions in an amount according to the instructions of the manufacturer. If the adjuvant is Specol an amount of e.g. 5, 10, 15, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000, 1500, or 2000 μl may be added to the immunogenic composition. Preferably, the adjuvant is mixed with water or buffer in an amount of about 1:1.

Amino acid: Any synthetic or naturally occurring amino carboxylic acid, including any amino acid occurring in peptides and polypeptides including proteins and enzymes synthesized in vivo. Natural amino acids comprise an amino terminal part (NH₂) and a carboxy terminal part (COON) separated by a central part comprising a carbon atom, or a chain of carbon atoms, comprising at least one side chain or functional group. NH₂ refers to the amino group present at the amino terminal end of an amino acid or peptide, and COON refers to the carboxy group present at the carboxy terminal end of an amino acid or peptide. The generic term amino acid comprises both natural and non-natural amino acids. Natural amino acids of standard nomenclature as listed in J. Biol. Chem., 243:3552-59 (1969) and adopted in 37 C.F.R., section 1.822(b)(2) belong to the group of amino acids listed in Table 2 herein below. Non-natural amino acids are those not listed in Table 2. Examples of non-natural amino acids are those listed e.g. in 37 C.F.R. section 1.822(b)(4), all of which are incorporated herein by reference.

Further examples of non-natural amino acids are listed herein below. Amino acid residues described herein can be in the “D” or “L” isomeric form.

TABLE 2 Natural amino acids and their respective codes. Symbols 1-Letter 3-Letter Amino acid Y Tyr tyrosine G Gly glycine F Phe phenylalanine M Met methionine A Ala alanine S Ser serine I Ile isoleucine L Leu leucine T Thr threonine V Val valine P Pro proline K Lys lysine H His histidine Q Gln glutamine E Glu glutamic acid W Trp tryptophan R Arg arginine D Asp aspartic acid N Asn asparagine C Cys cysteine U Sec selenocysteine O Pyl pyrrolysine

Amino acid residue: the term “amino acid residue” is meant to encompass amino acids, either standard amino acids, non-standard amino acids or pseudo-amino acids, which have been reacted with at least one other species, such as 2, for example 3, such as more than 3 other species. In particular amino acid residues may comprise an acyl bond in place of a free carboxyl group and/or an amine-bond and/or amide bond in place of a free amine group. Furthermore, reacted amino acids residues may comprise an ester or thioester bond in place of an amide bond

Amino acid precursor: Moiety capable of generating an amino acid residue following incorporation of the precursor into a peptide.

Antibody: Immunoglobulin molecule or immunologically active portion thereof, i.e. molecules that contain an “antigen binding site” or paratope. Immunoglobulins may be natural or wholly or partially synthetically produced. All fragments and derivatives thereof which maintain specific binding ability are also included in the term. The term also covers any polypeptide having a binding domain which is homologous or largely homologous, such as at least 95% identical, to an immunoglobulin binding domain. These polypeptides may be derived from natural sources, or partly or wholly synthetically produced. An antibody may be monoclonal or polyclonal. The antibody may be a member of any immunoglobulin class, including IgY, IgG, IgM, IgA, IgD, and IgE. Derivatives of the IgY class, however, are preferred in the present invention. An antibody that “specifically binds to” or is “specific for” a particular polypeptide or an epitope on a particular polypeptide is one that binds to that particular polypeptide or epitope on a particular polypeptide without substantially binding to any other polypeptide or polypeptide epitope. Antibodies can furthermore be described as plasma proteins that bind specifically to particular molecules known as antigens. Antibody molecules are produced by B lymphocytes in response to immunisation with antigen. They are the specific molecules of the humoral immune response that bind to and neutralize pathogens or prepare them for uptake and destruction by phagocytes. Each antibody molecule has a unique structure that allows it to bind its specific antigen, but all antibodies have the same overall structure and are known collectively as immunoglobulins. The body can make an almost unlimited variety of different antibodies, each B lymphocyte being genetically programmed early in its development to produce antibodies of a single specificity. A pool of antibodies according to the present invention can be obtained by immunising a single animal with a randomly generated peptide library. A randomly generated peptide library will in general stimulate an antibody response comprising antibodies with binding capability of (in theory) any antigen.

Antibody fragment: refers to any derivative of an antibody which is less than full-length. Preferably, the antibody fragment retains at least a significant portion of the full-length antibody's specific binding ability. Examples of antibody fragments include, but are not limited to, Fab, Fab′, F(ab′)₂, scFv, Fv, dsFv diabody, and Fd fragments. The antibody fragment may be produced by any means. For instance, the antibody fragment may be enzymatically or chemically produced by fragmentation of an intact antibody or it may be recombinantly produced from a gene encoding the partial antibody sequence. Alternatively, the antibody fragment may be wholly or partially synthetically produced. The antibody fragment may optionally be a single chain antibody fragment. Alternatively, the fragment may comprise multiple chains which are linked together, for instance, by disulfide linkages. The fragment may also optionally be a multimolecular complex. A functional antibody fragment will typically comprise at least about 50 amino acids and more typically will comprise at least about 200 amino acids.

Antibody specificity toward an antigen: According to the present invention an antibody can be termed antigen specific if e.g. antigen: antibody binding can be demonstrated in an assay as disclosed in Example 4, where antigen is linked to a carrier in the presence of PBS and antibodies are likewise suspended in a PBS buffer.

According to the present invention, at least about 1% of the antibodies obtained subsequent to immunisation show specificity to the antigens used for immunisation. If less than 1% of the antibodies show specificity to the antigens, antibodies may e.g. have been harvested too soon after immunisation, insufficient amounts of antigen have been employed, or inefficient amounts of adjuvants have been employed. More preferably, at least about 2, 3, 4, or 5% of the antibodies are antigens specific. Most preferably, at least about 6, 7, 8, 9, or 10% of the antibodies are specific. And most preferably about 20-30% of the antibodies are antigen specific.

Antigen: Any substance or molecule that can react with or bind to a specific antibody or specific antibodies. Conditions suitable for an antigen:antibody binding to take place are well known in the art. In the Examples, PBS buffer is employed.

Boost: To boost by a booster shot or dose is to give an additional dose of an immunizing agent, such as a vaccine, given at a time after the initial dose to sustain the immune response elicited by the previous dose of the same agent.

Bursa of Fabricius/Bursa fabricii: A thymus-like specialized lymphoid gland in birds that is an outgrowth of the cloaca and the site of hematopoiesis and B cell maturation in birds. It is thus the residence of antibody producing B cells.

Conjugated: An association formed between an immunogenic determinant and a carrier. The association may be a physical association generated e.g. by the formation of a chemical bond, such as e.g. a covalent bond, formed between the immunogenic determinant and the carrier.

Carriers: Entity or compound to which antigens are coupled to aid in the induction of an immune response. Conjugation to a carrier is important because peptides are small molecules that alone do not tend to be immunogenic, thus possibly eliciting a weak immune response. The carrier contains many epitopes that stimulate T-helper cells, which help induce the B-cell response. Many different carriers can be used for coupling to synthetic peptides. The most commonly selected carriers are keyhole limpet hemacyanin (KLH) and bovine serum albumin (BSA). The higher immunogenicity of KLH often makes it the preferred choice. Another advantage of choosing KLH over BSA is that BSA is used as a blocking agent in many experimental assays. Because antisera raised against peptides conjugated to BSA will also contain antibodies to BSA, false positives may result. Although KLH is large and immunogenic, it may precipitate during cross-linking, making it difficult to handle in some cases. Ovalbumin (OVA) is another useful carrier protein. It is a good choice as a second carrier protein when verifying whether antibodies are specific for the peptide alone and not the carrier. Rabbit Serum Albumin (RSA) may be used when the antibody response to the carrier protein must be kept to a minimum. Rabbits immunised with RSA conjugate are less likely to raise antibodies to the carrier, as the RSA is recognized as “self.” If the RSA conjugate were injected into another host, the protein would not be recognized as self. The same principle, of course, applies when immunising with chicken-derived carriers in chicken. It is important to recognize that the immune system reacts to the peptide-protein carrier as a whole and that there will be a portion of response directed against the conjugated peptide as well as the linker and the carrier. When screening by ELISA it is advisable to use a peptide conjugate prepared using a different carrier. This is not necessary if performing ELISA assays where the plates are coated directly with unconjugated peptide. Suitable carriers will thus be of protein origin in most cases. In some cases however, the carrier may be of non-protein origin such as e.g. polymers comprising carbohydrates, etc. It follows that it may not be necessary to conjugate relatively large peptides with a carrier in order to obtain an immune response. Peptides with a length of at least about 100 amino acids and more preferably with a length of at least about 150 amino acids may not need carrier conjugation in order to function as immunogens in the present invention. It is however advisable to conjugate all peptides with carrier molecules without regard to the size. Immunisation of the animal may be carried out with or without pharmaceutical carriers. Suitable carriers are typically large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers, lipid aggregates (such as oil droplets or liposomes), and inactive virus particles. Such carriers are well known to those of ordinary skill in the art. Additionally, these carriers may function as immunostimulating agents (“adjuvants”). See definition section “Adjuvant”.

Chemistry:

The term “hydrido” denotes a single hydrogen atom (H). This hydrido radical may be attached, for example, to an oxygen atom to form a hydroxyl radical or two hydrido radicals may be attached to a carbon atom to form a methylene (—CH₂—) radical.

Where the term “alkyl” is used, either alone or within other terms such as “haloalkyl” and “alkylsulfonyl”, it embraces linear or branched radicals having one to about twenty carbon atoms or, preferably, one to about twelve carbon atoms. Preferred alkyl radicals are “lower alkyl” radicals having one to about ten carbon atoms, such as lower alkyl radicals having one to about six carbon atoms. Examples of such radicals include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl and the like. Branched chain isomers of straight chain alkyl groups, include, but are not limited to, the following which are provided by way of example: —CH(CH₃)₂, —CH(CH)₃)(CH₂CH₃), —CH(CH₂CH₃)₂, —C(CH₃)₃, —C(CH₂CH₃)₃, —CH₂CH(CH₃)₂, —CH₂CH(CH₃)(CH₂CH₃), —CH₂CH(CH₂CH₃)₂, —CH₂C(CH₃)₃, —CH₂C(CH₂CH₃)₃, —CH(CH₃)CH(CH₃)(CH₂CH₃), —CH₂CH₂CH(CH₃)₂₃—CH₂CH₂CH(CH₃)(CH₂CH₃), —CH₂CH₂CH(CH₂CH₃)₂, —CH₂CH₂C(CH₃)₃, —CH₂CH₂C(CH₂CH₃)₃, —CH(CH₃)CH₂CH(CH₃)₂, —CH(CH₃)CH(CH₃)CH(CH₃)CH(CH₃)₂, —CH(CH₂CH₃)CH(CH₃)CH(CH₃)(CH₂CH₃), and others. When substituted, the “alkyl” or “lower alkyl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “alkenyl” embraces linear or branched radicals having at least one carbon-carbon double bond of two to about twenty carbon atoms, such as from two to about twelve carbon atoms, for example from two to about eight carbon atoms. Preferred alkyl radicals are “lower alkenyl” radicals having two to about six carbon atoms. Examples of such radicals include ethenyl, n-propenyl, butenyl, and the like. When substituted, the “alkenyl” or “lower alkenyl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “halo” means halogens such as fluorine, chlorine, bromine or iodine atoms. The term “haloalkyl” embraces radicals wherein any one or more of the alkyl carbon atoms is substituted with halo as defined above. Specifically embraced are monohaloalkyl, dihaloalkyl and polyhaloalkyl radicals. A monohaloalkyl radical, for one example, may have either an iodo, bromo, chloro or fluoro atom within the radical. Dihalo and polyhaloalkyl radicals may have two or more of the same halo atoms or a combination of different halo radicals. “Lower haloalkyl” preferably embraces radicals having 1-6 carbon atoms. Examples of haloalkyl radicals include fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, trichloromethyl, pentafluoroethyl, heptafluoropropyl, difluorochloromethyl, dichlorofluoromethyl, difluoroethyl, difluoropropyl, dichloroethyl and dichloropropyl. The “haloalkyl” or “lower haloalkyl” can optionally be further substituted. When further substituted, the “haloalkyl” or “lower haloalkyl” can further comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “hydroxyalkyl” embraces linear or branched alkyl radicals having from one to about ten carbon atoms any one of which may be substituted with one or more hydroxyl radicals. Hydroxyalkyl radicals can be “lower hydroxyalkyl” radicals preferably having one to six carbon atoms and one or more hydroxyl radicals. Examples of such radicals include hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl and hydroxyhexyl. The “hydroxyalkyl” or “lower hydroxyalkyl” can optionally be further substituted. When further substituted, the “hydroxyalkyl” or “lower hydroxyalkyl” can further comprise one or more radicals selected from the group of radicals consisting of primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The terms “alkoxy” and “alkoxyalkyl” embrace linear or branched oxy-containing radicals each having alkyl portions of one to about ten carbon atoms, such as methoxy radical. Alkoxy radicals can be “lower alkoxy” radicals having one to six carbon atoms. Examples of such radicals include methoxy, ethoxy, propoxy, butoxy and tert-butoxy.

The term “alkoxyalkyl” also embraces alkyl radicals having two or more alkoxy radicals attached to the alkyl radical, that is, to form monoalkoxyalkyl and dialkoxyalkyl radicals. Alkoxyalkyl radicals can be “lower alkoxyalkyl” radicals having one to six carbon atoms and one or two alkoxy radicals. Examples of such radicals include methoxymethyl, methoxyethyl, ethoxyethyl, methoxybutyl and metoxypropyl. The alkyl in said “alkoxyalkyl” can be substituted with one or more of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. When e.g. the above “alkoxyl” or “alkoxyalkyl” radicals are substituted with one or more halo atoms, such as fluoro, chloro or bromo, “haloalkoxy” or “haloalkoxyalkyl” radicals are provided. Examples of such radicals include fluoromethoxy, chloromethoxy, trifluoromethoxy, trifluoroethoxy, fluoroethoxy and fluoropropoxy.

The term “aryl”, alone or in combination, means a carbocyclic aromatic system containing one, two or three rings wherein such rings may be attached together in a pendent manner or may be fused. When substituted, “aryl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Examples of “aryl” include aromatic radicals such as phenyl, pentafluorphenyl, naphthyl, tetrahydronaphthyl, indane and biphenyl.

The term “heterocyclic” embraces saturated, partially saturated and unsaturated heteroatom-containing ring-shaped radicals, where the heteroatoms may be selected from nitrogen, sulfur and oxygen. When substituted, “heterocyclic” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Examples of saturated heterocyclic radicals include e.g. saturated 3 to 6-membered heteromonocylic group containing 1 to 4 nitrogen atoms [e.g. pyrrolidinyl, imidazolidinyl, piperidino, piperazinyl, etc.]; saturated 3 to 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms [e.g. morpholinyl, etc.]; saturated 3 to 6-membered heteromonocyclic group containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms [e.g. thiazolidinyl, etc.]. Examples of partially saturated heterocyclic radicals include dihydrothiophene, dihydropyran, dihydrofuran and dihydrothiazole.

The term “heteroaryl” embraces unsaturated heterocyclic radicals. When substituted, “heteroaryl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, secondary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Examples of unsaturated heterocyclic radicals, also termed “heteroaryl” radicals, include e.g. unsaturated 5 to 6 membered heteromonocyclic group containing 1 to 4 nitrogen atoms, for example, pyrrolyl, pyrrolinyl, imidazolyl, pyrazolyl 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazolyl [e.g., 4H-1,2,4-triazolyl, 1H-1,2,3-triazolyl, 2H-1,2,3-triazolyl, etc.] tetrazolyl [e.g. 1H-tetrazolyl, 2H-tetrazolyl, etc.], etc.; unsaturated condensed heterocyclic group containing 1 to 5 nitrogen atoms, for example, indolyl, isoindolyl, indolizinyl, benzimidazolyl, quinolyl, isoquinolyl, indazolyl, benzotriazolyl, tetrazolopyridazinyl [e.g., tetrazolo[1,5-b]pyridazinyl, etc.], etc.; unsaturated 3 to 6-membered heteromonocyclic group containing an oxygen atom, for example, pyranyl, 2-furyl, 3-furyl, etc.; unsaturated 5 to 6-membered heteromonocyclic group containing a sulfur atom, for example, 2-thienyl, 3-thienyl, etc.; unsaturated 5- to 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, for example, oxazolyl, isoxazolyl, oxadiazolyl [e.g., 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, etc.] etc.; unsaturated condensed heterocyclic group containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms [e.g. benzoxazolyl, benzoxadiazolyl, etc.]; unsaturated 5 to 6-membered heteromonocyclic group containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms, for example, thiazolyl, thiadiazolyl [e.g., 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,5-thiadiazolyl, etc.] etc.; unsaturated condensed heterocyclic group containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms [e.g., benzothiazolyl, benzothiadiazolyl, etc.] and the like. The term “heteroaryl” or “unsaturated heterocyclic radical” also embraces radicals where heterocyclic radicals are fused with aryl radicals. Examples of such fused bicyclic radicals include benzofuran, benzothiophene, and the like. Said “heterocyclic group” can be substituted with one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl, said substitution generating a substituted “heteroaryl”, optionally a substituted “heteroaryl” fused with an “aryl” radical which can be substituted or un-substituted. When substituted, the “aryl” is substituted as described herein above. Preferred heterocyclic radicals include five to ten membered fused or unfused radicals. More preferred examples or heteroaryl radicals include benzofuryl, 2,3-dihydrobenzofuryl, benzotrienyl, indolyl, dihydroindolyl, chromanyl, benzopyran, thiochromanyl, benzothiopyran, benzodioxolyl, benzodioxanyl, pyridyl, thienyl, thiazolyl, oxazolyl, furyl, and pyrazinyl.

The term “sulfonyl”, whether used alone or linked to other terms such as alkylsulfonyl, denotes respectively divalent radicals —SO₂—.

“Alkylsulfonyl” embraces alkyl radicals attached to a sulfonyl radical, where alkyl can be substituted is defined as above. Alkylsulfonyl radicals can be “lower alkylsulfonyl” radicals having one to six carbon atoms. Examples of such lower alkylsulfonyl radicals include methylsulfonyl, ethylsulfonyl and propylsulfonyl.

The term “arylsulfonyl” embraces aryl radicals as defined above, including substituted aryl radicals, attached to a sulfonyl radical. Examples of such radicals include phenylsulfonyl.

The terms “sulfamyl,” “aminosulfonyl” and “sulfonamidyl,” whether alone or used with terms such as “N-alkylaminosulfonyl”, “N-arylaminosulfonyl”, “N,N-dialkylaminosulfonyl” and “N-alkyl-N-arylaminosulfonyl”, denotes a sulfonyl radical substituted with an amine radical, forming a sulfonamide (—SO₂NH₂).

The terms “N-alkylaminosulfonyl” and “N,N-dialkylaminosulfonyl” denote sulfamyl radicals substituted respectively, with one alkyl radical, or two alkyl radicals, optionally substituted alkyl radicals as described herein above. Alkylaminosulfonyl radicals can be “lower alkylaminosulfonyl” radicals having one to six carbon atoms. Examples of such lower alkylaminosulfonyl radicals include N-methylaminosulfonyl, N-ethylaminosulfonyl and N-methyl-N-ethylaminosulfonyl.

The terms “N-arylaminosulfonyl” and “N-alkyl-N-arylaminosulfonyl” denote sulfamyl radicals substituted, respectively, with one aryl radical, or one alkyl and one aryl radical, optionally substituted aryl and/or alkyl radicals as described herein above. N-alkyl-N-arylaminosulfonyl radicals can be “lower N-alkyl-N-arylsulfonyl” radicals having alkyl radicals of one to six carbon atoms. Examples of such lower N-alkyl-N-aryl aminosulfonyl radicals include N-methyl-phenylaminosulfonyl and N-ethyl-phenylaminosulfonyl.

The terms “carboxy” or “carboxyl”, whether used alone or with other terms, such as “carboxyalkyl”, denotes —CO₂H.

The term “carboxyalkyl” or “alkanoyl” embraces radicals having a carboxy radical as defined above, attached to an alkyl radical as described herein above. When substituted, the “alkyl” or “lower alkyl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Examples of “carboxyalkyl” radicals include formyl, acetyl, propionyl (propanoyl), butanoyl (butyryl), isobutanoyl (isobutyryl), valeryl (pentanoyl), isovaleryl, pivaloyl, hexanoyl or the like.

The term “carbonyl”, whether used alone or with other terms, such as “alkylcarbonyl”, denotes —(C═O)—.

The term “alkylcarbonyl” embraces radicals having a carbonyl radical substituted with an alkyl radical. Alkylcarbonyl radicals can be “lower alkylcarbonyl” radicals having from one to six carbon atoms. Examples of such radicals include methylcarbonyl and ethylcarbonyl. When substituted, the “alkyl” or “lower alkyl” of the “alkylcarbonyl” can comprise one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, and thiolyl.

The term “alkylcarbonylalkyl”, denotes an alkyl radical substituted with an “alkylcarbonyl” radical as described herein above. Both the alkyl and the alkylcarbonyl can be substituted as described herein above.

The term “alkoxycarbonyl” means a radical containing an alkoxy radical, as defined above, attached via an oxygen atom to a carbonyl radical. “Lower alkoxycarbonyl” embraces alkoxy radicals preferably having from one to six carbon atoms. Examples of “lower alkoxycarbonyl” ester radicals include substituted or unsubstituted methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl and hexyloxycarbonyl.

The term “alkoxycarbonylalkyl” embraces radicals having “alkoxycarbonyl”, as defined above substituted to an optionally substituted alkyl radical. Alkoxycarbonylalkyl radicals can be “lower alkoxycarbonylalkyl” having lower alkoxycarbonyl radicals as defined above attached to one to six carbon atoms. Examples of such lower alkoxycarbonylalkyl radicals include methoxycarbonylm ethyl, tert-butoxycarbonylethyl, and methoxycarbonylethyl.

The term “aminocarbonyl” when used by itself or with other terms such as “aminocarbonylalkyl”, “N-alkylaminocarbonyl”, “N-arylaminocarbonyl, “N,N-dialkylaminocarbonyl”, “N-alkyl-N-arylaminocarbonyl”, “N-alkyl-N-hydroxyaminocarbonyl” and “N-alkyl-N-hydroxyaminocarbonylalkyl”, denotes an amide group of the formula —C(═O)NH₂.

The terms “N-alkylaminocarbonyl” and “N,N-dialkylaminocarbonyl” denote aminocarbonyl radicals which have been substituted with one alkyl radical and with two alkyl radicals, respectively. The alkyl radicals can be substituted as described herein above. “Lower alkylaminocarbonyl” comprises lower alkyl radicals as described above attached to an aminocarbonyl radical.

The terms “N-arylaminocarbonyl” and “N-alkyl-N-arylaminocarbonyl” denote aminocarbonyl radicals substituted, respectively, with one aryl radical, or one alkyl and one aryl radical, wherein such radicals can be substituted as described herein above.

The term “aminocarbonylalkyl” embraces optionally substituted alkyl radicals substituted with aminocarbonyl radicals.

The term “N-cycloalkylaminocarbonyl” denotes aminocarbonyl radicals which have been substituted with at least one optionally substituted cycloalkyl radical. “Lower cycloalkylaminocarbonyl” comprises lower cycloalkyl radicals of three to seven carbon atoms, attached to an aminocarbonyl radical.

The term “aminoalkyl” embraces alkyl radicals substituted with one or more amino radicals. The alkyl radicals can be further substituted by one or more radicals selected from the group of radicals consisting of hydroxy, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “alkylaminoalkyl” embraces aminoalkyl radicals having the nitrogen atom substituted with an optionally substituted alkyl radical.

The term “amidino” denotes an —C(═NH)—NH₂ radical.

The term “cyanoamidino” denotes an —C(═N—CN)—NH₂ radical.

The term “heterocyclicalkyl” embraces heterocyclic-substituted alkyl radicals. The alkyl radicals can themselves be substituted by one or more radicals selected from the group of radicals consisting of hydroxy, primary amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Heterocyclicalkyl radicals can be “lower heterocyclicalkyl” radicals preferably having from one to six carbon atoms and a heterocyclic radical. Examples include such radicals as pyrrolidinylmethyl, pyridylmethyl and thienylmethyl.

The term “aralkyl” embraces aryl-substituted alkyl radicals. The alkyl radicals can themselves be substituted by one or more radicals selected from the group of radicals consisting of hydroxy, primary amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Aralkyl radicals can be “lower aralkyl” radicals having aryl radicals attached to alkyl radicals having from one to six carbon atoms. Examples of such radicals include benzyl, diphenylmethyl, triphenylmethyl, phenylethyl and diphenylethyl. The aryl in said aralkyl may be additionally substituted with halo, alkyl, alkoxy, halkoalkyl and haloalkoxy. The terms benzyl and phenylmethyl are interchangeable.

The term “cycloalkyl” embraces radicals having three to ten carbon atoms. Cycloalkyl radicals can be “lower cycloalkyl” radicals having three to seven carbon atoms. Examples include radicals such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. The “cycloalkyl” can optionally be substituted by one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “cycloalkenyl” embraces unsaturated cyclic radicals having three to ten carbon atoms. The “cycloalkenyl” can optionally be substituted by one or more radicals selected from the group of radicals consisting of hydroxy, primary amine, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Examples include cyclobutenyl, cyclopentenyl, cyclohexenyl and cycloheptenyl, which can optionally be substituted as described above.

The term “alkylthio” embraces radicals containing a linear or branched alkyl radical, of one to ten carbon atoms, attached to a divalent sulfur atom. An example of “alkylthio” is methylthio, (CH₃—S—). The alkyl radical can be substituted as described herein above.

The term “alkylsulfinyl” embraces radicals containing a linear or branched alkyl radical, of one to ten carbon atoms, attached to a divalent —S(═O)— atom. The alkyl radical can be substituted as described herein above.

The term “aminoalkyl” embraces alkyl radicals substituted with amino radicals. The alkyl radicals can be further substituted by one or more radicals selected from the group of radicals consisting of hydroxy, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl. Aminoalkyl radicals can be “lower aminoalkyl” having from one to six carbon atoms. Examples include aminomethyl, aminoethyl and aminobutyl which can optionally be further substituted as described above.

The term “alkylaminoalkyl” embraces aminoalkyl radicals having the nitrogen atom substituted with at least one alkyl radical. Alkylaminoalkyl radicals can be “lower alkylaminoalkyl” having one to six carbon atoms attached to a lower aminoalkyl radical as described above. The alkyl radical can be substituted as described herein above.

The terms “N-alkylamino” and “N,N-dialkylamino” denote amino groups which have been substituted with one alkyl radical and with two alkyl radicals, respectively. The alkyl radical can be substituted as described herein above. Alkylamino radicals can be “lower alkylamino” radicals having one or two alkyl radicals of one to six carbon atoms, attached to a nitrogen atom. Suitable “alkylamino” may be mono or dialkylamino such as N-methylamino, N-ethylamino, N,N-dimethylamino, N,N-diethylamino or the like.

The term “arylamino” denotes amino groups which have been substituted with one or two aryl radicals, such as N-phenylamino. The “arylamino” radicals may be further substituted on the aryl ring portion of the radical. Substitutions can include one or more of hydroxy, amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “aralkylamino” denotes amino groups which have been substituted with one or two aralkyl radicals, such as N-benzylamino. The “aralkylamino” radicals may be further substituted on the aryl ring portion of the radical. Substitutions can include one or more of hydroxy, amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The terms “N-alkyl-N-arylamino” and “N-aralkyl-N-alkylamino” denote amino groups which have been substituted with one aralkyl and one alkyl radical, or one aryl and one alkyl radical, respectively, to an amino group. The aralkyl and/or alkyl and/or aryl radicals can be substituted as described herein above.

The terms “N-arylaminoalkyl” and “N-aralkylaminoalkyl” denote amino groups which have been substituted with one aryl radicals or one aralkyl radical, respectively, and having the amino group attached to an alkyl radical. The aralkyl and/or alkyl and/or aryl radicals can be substituted as described herein above. Arylaminoalkyl radicals can be “lower arylaminoalkyl” having the arylamino radical attached to one to six carbon atoms. Examples of such radicals include N-phenylaminomethyl and N-phenyl-N-methylaminomethyl.

The terms “N-alkyl-N-arylaminoalkyl”, and “N-aralkyl-N-alkylaminoalkyl” denote N-alkyl-N-arylamino and N-alkyl-N-aralkylamino groups, respectively, and having the amino group attached to alkyl radicals which can be substituted as described herein above.

The term “acyl”, whether used alone, or within a term such as “acylamino”, denotes a radical provided by the residue after removal of hydroxyl from an organic acid.

The term “acylamino” embraces an amino radical substituted with an acyl group. An examples of an “acylamino” radical is acetylamino or acetamido (CH₃C(═O)—NH—) where the amine may be further substituted with alkyl, aryl or aralkyl, wherein said alkyl, aryl or aralkyl can be substituted as described herein above.

The term “arylthio” embraces aryl radicals of six to ten carbon atoms, attached to a divalent sulfur atom. The aryl can be substituted as described herein above. An example of “arylthio” is phenylthio.

The term “aralkylthio” embraces aralkyl radicals as described above, attached to a divalent sulfur atom. The aralkyl radicals can be further substituted as described herein above. An example of “aralkylthio” is benzylthio.

The term “aryloxy” embraces aryl radicals, as defined above, attached to an oxygen atom. The aryl can be substituted as described herein above. Examples of such radicals include phenoxy.

The term “aralkoxy” embraces oxy-containing aralkyl radicals attached through an oxygen atom to other radicals. The aralkyl can be substituted as described herein above. Aralkoxy radicals can be “lower aralkoxy” radicals having phenyl radicals attached to lower alkoxy radical as described above.

The term “haloaralkyl” embraces aryl radicals as defined above attached to haloalkyl radicals. The aryl can be further substituted as described herein above.

The term “carboxyhaloalkyl” embraces carboxyalkyl radicals as defined above having halo radicals attached to the alkyl portion. The alkyl portion can be further substituted as described herein above.

The term “alkoxycarbonylhaloalkyl” embraces alkoxycarbonyl radicals as defined above substituted on a haloalkyl radical. The haloalkyl radical can be further substituted by one or more of hydroxy, amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “aminocarbonylhaloalkyl” embraces aminocarbonyl radicals as defined above substituted on an optionally substituted haloalkyl radical wherein the alkyl is substituted by one or more of hydroxy, amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “alkylaminocarbonylhaloalkyl” embraces alkylaminocarbonyl radicals as defined above substituted on an optionally substituted haloalkyl radical as described above.

The term “alkoxycarbonylcyanoalkenyl” embraces alkoxycarbonyl radicals as defined above, and a cyano radical, both substituted on an optionally substituted alkenyl radical.

The term “carboxyalkylaminocarbonyl” embraces aminocarbonyl radicals substituted with carboxyalkyl radicals, as defined above. The carboxyalkyl can be further substituted. Substitutions can include one or more of hydroxy, amino, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

The term “aralkoxycarbonylalkylaminocarbonyl” embraces aminocarbonyl radicals substituted with aryl-substituted alkoxycarbonyl radicals, as defined above.

The term “cycloalkylalkyl” embraces cycloalkyl radicals having three to ten carbon atoms attached to an alkyl radical, as defined above. Cycloalkylalkyl radicals can be “lower cycloalkylalkyl” radicals having cycloalkyl radicals attached to lower alkyl radicals as defined above. Examples include radicals such as cyclopropylmethyl, cyclobutylmethyl, and cyclohexylethyl.

The term “aralkenyl” embraces optionally substituted aryl radicals attached to alkenyl radicals having two to ten carbon atoms, such as phenylbutenyl, and phenylethenyl or styryl. When substituted the aryl can be substituted with one or more of hydroxy, amino, carboxy, acid chloride, sulfonyl chloride, sulphonate, nitro, cyano, isothiocyanate, halogen, phosphonyl, sulphonyl, sulfamyl, carbonyl, and thiolyl.

Co-immunization: Immunization by means of separate and/or sequential administration to an individual of an immunogenic determinant and a carrier.

“Conditions suitable for binding”: means those conditions (in terms of salt concentration, pH, detergent, polypeptide concentration, temperature, etc.) which allow for binding to occur between a ligand and its binding partner in solution i.e. the bidning between an antigen and an antibody. Preferably, the conditions are not so lenient that a significant amount of nonspecific binding occurs.

Derivative: refers to polypeptides derived from naturally occurring XXX by chemical modifications such as ubiquitination, labeling (e.g., with radionuclides, various enzymes, etc.), pegylation (derivatization with polyethylene glycol), or by insertion (or substitution by chemical synthesis) of amino acids (amino acids) such as ornithine, which do not normally occur in human proteins.

Elution: By using different elution conditions, the method allows an approximate quantification of the binding affinity of the monoclonal antibody for its binding partner. Elution agents that may be used include chaotropic agents such as guanidine hydrochloride or urea at concentrations between 10 μM and 8 M or ethylene glycol in an aqueous solution of 0.01% to 100% w/v. Elutions may also be carried out using aqueous or non-aqueous solutions of glycine. Elutions may be carried out using aqueous or non aqueous solutions of triethylamine between 1 μM and a saturated solution, preferably 100 mM, at a pH of between pH 8 and pH 13, preferably pH 11.5.

Epitope: A specific site on a protein to which only certain antibodies bind.

Galliformes: The order of birds that includes grouse, ptarmigan, capercaillie, partridges, pheasants, quails, turkeys and peacocks. These are mainly grain-eating, heavy-bodied, ground-nesting birds, capable of only short, rapid flights. The cocks are usually more colourful than the hens. A preferred bird according to the present invention is a hen (Gallus gallus domestica) either in the adult stage or as a chicken at the age of at least 17-19 weeks.

Host: as used herein is any species immunized and used for the production of an antibody library according to the present invention. The term includes any animal, mammalian or vertebrate. Herein the preferred host is an avian species and preferably a female of the species.

Immunization: Process of inducing an immunological response in an organism by the introduction of an antigen into the animal by any suitable means. Preferably, the method of introduction involves injection. The animals may be immunised with the antigens intrasplenically, intravenously, intraperitoneally, intradermal̂ or subcutaneously or by any other suitable means. For practical and economical reasons, chickens kept under field conditions are vaccinated intramusculary in the breast muscle. In the laboratory, chickens can also be vaccinated subcutaneously in the neck.

The total number of immunisations will depend upon the type and dose of the antigen, as well as on the particular adjuvant employed. In a preferred embodiment, at least two immunisations should be given. If the antibody titres begin to decrease, booster immunisations can be given. The total amount of peptide employed for each immunisation may likewise vary. Amounts of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, or 500 μg are preferably used in a single immunisation. But amounts of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75, 100, 125, 150, 175, 200, 250, or 500 mg may also be used in a single immunisation.

Immunological response: Response to an immunogenic composition comprising an immunogenic determinant. An immune response involves the development in the host of a cellular- and/or antibody-mediated response to the administered composition or vaccine in question. An immune response generally involves the action of one or more of i) the antibodies raised, ii) B cells, iii) helper T cells, iv) suppressor T cells, and v) cytotoxic T cells, directed specifically to an immunogenic determinant present in an administered immunogenic composition.

Immunogenic composition: Composition capable of raising an immunological response in an individual.

Immunogenic: Functionality associated with an entity capable of eliciting an immunological response.

Immunostimulating effect: Functionality associated with an entity capable of eliciting an enhanced immune response. An enhanced immune response will be understood within the meaning of the observed difference in the immune response measured as an enhancement of an antibody production and/or a cytotoxic T-cell activity, or otherwise registered, when an immunogenic composition is administered in the presence or absence, respectively, of the entity. An immunogenic composition comprising the entity will be understood as being a composition according to the present invention.

Individual: Any species or subspecies of bird, mammal, fish, amphibian, or reptile.

Isolated: used in connection with, polypeptides, and antibodies disclosed herein ‘isolated’ refers to these having been identified and separated and/or recovered from a component of their natural, typically cellular, environment. Nucleic acids, polypeptides, and antibodies of the invention are preferably isolated, and vaccines and other compositions of the invention preferably comprise isolated nucleic acids, polypeptides or isolated antibodies.

Isolated polypeptide: a protein, or a variant or fragment thereof, which constitutes 90% or more of the protein contents of a given preparation as evaluated by standard methods known in the art of protein chemistry.

A polypeptide “fragment”, “portion”, or “segment”: is a stretch of amino acid residues of at least about 5 amino acids, often at least about 7 amino acids, typically at least about 9 to 13 amino acids, such as at least about 17 or more amino acids in various embodiments. To be active, any polypeptide, peptide or polypeptide fragment must have sufficient length to display biologic and/or immunologic activity on their own, or when conjugated to a carrier.

Library: a plurality of entities such as antigens or antibodies

Ligand: In biochemistry, a ligand is an effector, a molecule that binds to a site on a macromolecule's surface by intermolecular forces, thereby changing the chemical conformation of the macromolecule. Once a molecule's conformation has changed, its ability to function in other chemical reactions is altered. This binding is usually a reversible reaction, i.e. it can be undone. Actual coordinate covalent bonds between a ligand and its target molecule are rare in biological systems. Ligands include substrates, inhibitors, activators, and neurotransmitters. Herein an antigen is a ligand to an antibody.

Monoclonal antibody: (mAB) A single type of antibody that is directed against a specific epitope (antigen, antigenic determinant) and is produced by a single clone of B cells or a single hybridoma cell line, which is formed by the fusion of a lymphocyte cell with a myeloma cell. Some myeloma cells synthesize single antibodies naturally.

Non-natural amino acid: Any amino acid not included in Table 2 herein above. Non-natural amino acids include, but are not limited to modified amino acids, pseudo-amino acids, L-amino acids, and stereoisomers of D-amino acids.

Non-standard amino acid: a non-standard amino acid is capable of being incorporated into a peptide or peptide like structure by translation mediated by a ribosome. A non-standard amino acid according to the present invention is any amino acid comprising an amino group and a carboxyl group separated by an α-carbon. The amino acid may for example be selected from the group consisting of, Aib, NaI, Sar, Orn, Lysine analogues DAP and DAPA or any of the amino acids described in U.S. Pat. No. 5,573,905. Furthermore, non-standard amino acids may be any of the above mentioned or any standard amino acids which further comprises one or more moieties selected from the group consisting of hydroxyl, bromo, fluoro, chloro, iodo, mercapto, thio, cyano, alkylthio, heterocycle, aryl, heteroaryl, carboxyl, carboalkoyl, alkyl, alkenyl, nitro, amino, alkoxyl and/or amido. The non-standard amino acid is capable of being incorporated into a peptide or peptide like structure by translation mediated by a wt, mutant, modified or recombinant ribosome.

Normal physiological condition: means conditions that are typical inside a living organism or a cell. While it is recognized that some organs or organisms provide extreme conditions, the intra-organismal and intracellular environment normally varies around pH 7 (i.e., from pH 6.5 to pH 7.5), contains water as the predominant solvent, and exists at a temperature above 0° C. and below 50° C. It will be recognized that the concentration of various salts depends on the organ, organism, cell, or cellular compartment used as a reference.

Nucleic acid: A chain or sequence of nucleotides that convey genetic information. In regards to the present invention the nucleic acid is a deoxyribonucleic acid (DNA).

Nucleic acid construct: A genetically engineered nucleic acid. A (nucleic acid) construct typically comprises several elements such as genes or fragments of same, promoters, enhancers, terminators, polyA tails, linkers, markers or others.

Peptide: Plurality of covalently linked amino acid residues defining a sequence and linked by amide bonds. The term is used analogously with oligopeptide and polypeptide. The amino acids may be both natural amino acids and non-natural amino acids, including any combination thereof. The natural and/or non-natural amino acids may be linked by peptide bonds or by non-peptide bonds. The term peptide also embraces post-translational modifications introduced by chemical or enzyme-catalyzed reactions, as are known in the art. Such post-translational modifications can be introduced prior to partitioning, if desired. Amino acids as specified herein will preferentially be in the L-stereoisomeric form. Amino acid analogs can be employed instead of the 20 naturally-occurring amino acids. Several such analogs are known, including fluorophenylalanine, norleucine, azetidine-2-carboxylic acid, S-aminoethyl cysteine, 4-methyl tryptophan and the like.

Peptide antigen: Peptides according to the present invention are defined as peptides with a length of at least 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acids. Peptides according to the present invention may also have lengths of about 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600 amino acids or more. The peptides used as antigens according to the invention can be a mix of peptides of different lengths, i.e. there may be short peptides present with a length as short as 6 amino acids as well as longer peptides. Some or all of the peptides may also be in form of proteins being either denatured or in their naturally folded form. It follows that proteins can be obtained from either a natural source or they can be recombinantly produced and subsequently purified. The peptides may in addition comprise any form of modifications such as e.g. glycosylation, lipid attachment, hydroxylation, disulfide bonding, phosphorylation, etc. The peptides may also originate from a proteolytical digest of peptides and/or proteins. Antigens according to the present invention are in other words of peptide origin with a length at or above 6 amino acids, and may be derived either from natural sources, produced by recombinant methods, or synthesized artificially—or any mixtures thereof. It is however important that the peptides used for immunisation in connection with the present invention are substantially free from e.g. contaminating cellular debris. Thus, the present invention does not relate to immunisation with antigens derived from cellular material including cell membranes, nucleic acids, etc. The amount of different peptide antigens used for immunisation of the animal is at least 15. As the aim of the present invention is to provide tools for rapidly isolating antigen specific antibodies, it is advantageous to immunise with even more antigens, as the likelihood thus increases of obtaining antibodies with specificity to most antigens. It is therefore preferable to immunise with at least about 25, 50, 100, 150, 200, 250, 500, 1000, 5000, 10000, 50000, 100000, 500000, 1000000, or 5000000 different antigens. It is most preferable to immunise with a synthetically synthesized peptide library comprising, in theory, about 20⁶ or more different peptide combinations.

Peptide library: A preferred way of carrying out the present invention is to synthesize a peptide library with peptides of similar lengths covering the possible amino acid combinations of the 20 naturally occurring amino acids. Peptide synthesis may take place in solution or on a solid phase. A peptide library with peptides of a length of e.g. 6 naturally occurring amino acids will thus in theory have 20⁶ different ways of combining the amino acids, and thus up to 20⁶ different peptides. The peptide library may also be a library comprising e.g. a specific fraction of the amino acid sequence from a number of different proteins with known sequences. The peptides must have lengths of at least 6 amino acids in order to be able to bind to the hyper variable loops of the Fab fragment of the antibody. It follows that peptide libraries may also be prepared using less than 20 amino acids—in which case of course the theoretical number of different combinations will vary accordingly.

Pharmaceutical carriers, excipients, or stabilizers which are non-toxic to the cell or mammal being exposed thereto at the dosages and concentrations employed. Often the physiologically acceptable carrier is an aqueous pH buffered solution. Examples of physiologically acceptable carriers include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as TWEEN™, polyethylene glycol (PEG), and PLURONICS™

Plurality: At least two.

Polyclonal antibody: Polyclonal antibodies are a pool of immunoglobulins which arise from more than one clone of B-lymphocyte cells

Polypeptide derivatives: polypeptides derived from naturally occurring XXX by chemical modifications such as ubiquitination, labeling (e.g., with radionuclides, various enzymes, etc.), pegylation (derivatization with polyethylene glycol), or by insertion (or substitution by chemical synthesis) of amino acids (amino acids) such as ornithine, which do not normally occur in human proteins.

Pseudo-amino acid: an entity comprising a substituted amino group or/and carboxyl group separated by an α-carbon or α-amine capable of being incorporated into a peptide by ribosomes. For example, a pseudo amino acid may comprise a thiol group and a carboxyl group separated by an α-carbon resulting in a thioester bond in the backbone.

Residue: A polymer comprises a sequence of covalently linked residues, wherein each residue comprises a functional group.

Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading phase. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice.

Surfactant: A surface active agents capable of reducing the surface tension of a liquid in which it is dissolved. A surfactant is a compound containing a polar group which is hydrophilic and a non polar group which is hydrophobic and often composed of a fatty chain.

Vaccine/immunization cocktail/immunogenic composition: A substance or composition capable of inducing an immune response in an animal/host. An immune response being an immune response (humoral/antibody and/or cellular) inducing memory in an organism, resulting in the generation of antibodies against the introduced agents/antigens. The composition may comprise one or more of the following: antigen(s), carriers, adjuvants and pharmaceutical carriers.

Variant: a variant of a given reference nucleic acid or polypeptide refers to a nucleic acid or polypeptide that displays a certain degree of sequence homology to said reference nucleic acid or polypeptide but is not identical to said reference nucleic acid or polypeptide.

Vertebrate animal: A vertebrate animal is herein to be understood as an animal from the vertebrate phylae. Preferred animals are animals from either the mammalian or the avian orders. Avian animals are particularly preferred. Birds from the Galliformes order are most preferred. Birds used for immunisation should have an age of at least 17 weeks, preferably at least 19 weeks.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an ELISA standard curve.

DETAILED DESCRIPTION OF THE INVENTION the Method of Antibody Library Construction

The present invention relates to a novel method of constructing a library of antibodies in a fast and inexpensive manner by immunizing each of a plurality of avian organisms of the same or a different species with a composition comprising a plurality of different antigens capable of raising in each avian organism a plurality of different IgY antibodies, and collecting said different IgY antibodies from eggs laid by said plurality of avian organisms.

Thus, in a first aspect, the present invention relates to a method of obtaining polyclonal antibodies comprising antigen specific antibodies, wherein said method comprises the following steps:

(a) immunising a vertebrate animal with a composition comprising: (i) about 15 or more different peptide antigens, said peptides being conjugated with a carrier and having a length of at least 6 amino acids, and (ii) an adjuvant, (b) collecting a pool of polyclonal antibodies from the animal, wherein a fraction of about 1% or more show reactivity towards the antigens used for immunisation.

The principle of immunising an animal, preferably a bird of the gallinacean type, and most preferably of the species Gallus gallus domestica with a large amount of different antigens is a principle that provides tools for obtaining polyclonal antibodies in a much more fast and inexpensive way than previously known methods. The “antibody library” can subsequently be used for isolating polyclonal antibodies with a desired specificity. After having isolated specific polyclonal antibodies, the antibody library can be stored for later usage and the library can thus be “recycled” in an (in theory) indefinite number of times. It follows, that it is much faster to isolate antigen specific antibodies from an antibody library which in theory comprises antibodies that have antibody binding capability to almost any antigen—rather than immunising the animal and waiting several weeks for a specific antibody response.

A preferred way of obtaining an antibody library is by immunising with a peptide library obtainable by synthesizing peptides with a length of at least 6 amino acids. Likewise, the peptide antigen may also be a mix of peptides with different lengths. The hen is ideal because it can produce about 1500 mg antibodies per month (about 50-100 mg antibodies per egg (AOEA 24: 925-934, 1996). In fact, antibodies can be obtained in a non-invasive manner from the chicken during the entire egg-laying period. Usually, about 2-10% of the antibodies are antigen specific (AOEA 24: 925-934, 1996). The percentage of antigen specific antibodies may be even higher as a response to immunisation with a multitude of antigens.

The antibody library thus constructed will in the first instance be a library of polyclonal antibodies comprising a plurality of antibodies of different specificities in accordance with the number of antigens the host will be immunized with.

Prior to the construction of the antibody library, one or more libraries of antigens are synthesized. If the library is a peptide library this may be done by random peptide synthesis. Subsequently the antigens may be coupled to a carrier optionally in combination with one or more adjuvants and used for the immunization of the host animals. The host animals are preferably the hens of an avian species. The antibodies generated by each hen are isolated from the yolk of the eggs laid by the immunized hens. All the antibodies thus collected are pooled and this pool constitutes a polyclonal antibody library. A monoclonal library may also be constructed as described in the below. From the antibody libraries thus generated, antibodies specific for virtually any antigen can be isolated.

The antibody library can subsequently be used for isolating polyclonal antibodies with a desired specificity. The specificity does not have to reflect the antigens used during immunization. As the number of antibodies of varying specificity is high, any compound may find its complementary antibody comprised within the library. In this manner, antibodies against compounds that otherwise may not or can not be used for immunization may be found. Specific antibodies can be harvested from the library according to the methods described in the below. Furthermore, the antibody library can be reused as a source of specific antibodies repeatedly, in theory an indefinite number of times. It follows, that it is much faster to isolate antigen specific antibodies from an antibody library which in theory comprises antibodies that have antibody binding capability to virtually any antigen—rather than immunizing the animal and waiting weeks to months for a specific antibody response. Thus the present invention provides a method of obtaining specific polyclonal and/or monoclonal antibodies in a much faster and significantly less expensive way than is currently employed.

According to theory, a complete antibody library will contain approximately 5.8×10⁶ different antibodies as defined by different binding domains. This number is the result of the different possible combinations of the variable regions, heavy and light chains of the antibodies. From this number, the antibody binding domains that recognize species specific sequences must be subtracted, since a species normally does not produce antibodies against itself. The exact number that has to be subtracted is unknown. It is expected that the immune system of an avian species reacts against at least 1.000 of 10.000 introduced antigens. Similar reactions are observed when animals react against different diseases at the same time. During immunization about 1 in 1000 lymphoid cells are activated. The chicken immune system contains app. 10⁹ lymphoid cells, and as one in a thousand in theory should be activated, 1.000.000 cells are predicted to be able to react to a maximal stimulus. This is enough for reaction against 10.000 antigens.

The immunized birds are used for antibody production for an extended period of time such as about one year during which egg-laying is at its maximum. After this period, the birds are killed and their bursas of Fabricius are harvested. This organ is a specialized organ that is the site of hematopoiesis in birds, which is the residence of the antibody producing B cells. These antibody producing cells may be fused to a myeloma cell line, thus creating a hybridoma cell line that produces specific antibodies. As each individual B cell and its immediate derivates—a specific B cell clone—only produce one type of antibody, these hybridoma cells are the source of monoclonal antibodies. In this manner monoclonal antibodies can be harvested and pooled into a library of monoclonal antibodies.

By isolating specific antibody-producing cells employing the purification method used for antibody purification it is possible to produce monoclonal antibodies fast and cheap without difficult screening procedures and time consuming immunization. The production time is expected to be around 14 days, and the costs of the monoclonal antibodies will be similarly reduced compared to traditional techniques of isolating monoclonal antibodies.

A further advantage of using avian species for the rapid production of antibody libraries, both poly- and monoclonal, is the avian specific immunoglobulin molecule, IgY. Although the terms IgG and IgY are commonly interchanged when speaking of chicken immunoglobulin, the accepted term is IgY. Chicken IgY is the functional equivalent to mammalian IgG. Immunoglobulins from chickens and other avian species bear some resemblance to mammalian IgG, but also display some unique structural and functional characteristics that distinguish them from IgG. Of similarities the following can be mentioned: IgY is divalent, degraded by papain to yield divalent Fab fragment and may be labeled i.e. enzyme-labeled, biotinylated and gold-labeled by standard procedures. It is found in the serum of chickens and is passed from the mother chicken to the embryo via the egg yolk, imparting a high concentration of chicken IgY to developing embryo. The “Y” in IgY comes from “yolk” and is the main antibody component in the egg yolk. Each yolk can yield 100-150 mg of antibody. As a measure of the amount of antibodies that may be produced according to the present invention, consider the following: A chicken produces around 100 mg IgY/egg, which corresponds to 30 g IgY per year. Depending on the number of birds immunized, kilograms of polyclonal antibodies may thus be harvested. Furthermore, the IgY molecule is more stable than the traditionally used IgG molecules and IgY has less cross-reactivity toward mammalian proteins. IgY does not bind rheumatoid factors or Fc-receptors nor proteins A or G, therefore the chicken's antibodies are unlikely to produce false positive reactions in certain immunochemical assays. Also, unlike mice, rabbits or other mammals, hens elicit a strong antibody response against highly conserved mammalian protein sequences, and the IgY's can be obtained without sacrificing or bleeding the animal.

Antigens

The antigens of the present invention are may comprise any compound capable of eliciting an immune response in an animal, said animal preferably being an avian. Examples of compounds thus included are natural and non-natural amino aid residues, and combinations of these as natural amino acids only, as non-natural amino acids only or combination of either together into peptides or peptide-like compounds. Among the non-natural amino acids are the “unnatural” amino acids described by Mendel et al., (Annu. Rev. Biophys. Biomol. Struct. 1995 24:435-62—the document is hereby incorporated by reference and of special relevance for the present invention are the amino acids illustrated in FIG. 3 of said document). Be noted, that among these non-natural amino acids are acids, that do not comprise an amino (—NH2) group, these are also included as moieties of the present invention. Preferably, the moieties of the present invention are naturally occurring amino acids.

The naturally occurring amino acids of the invention may be synthetically prepared and linked or may be the result of proteolytic cleavage of any type of protein that may be isolated from any type of organism. An aspect of the present invention relates to antigens and/or proteins derived from organisms. These organisms may be any organism, such as pathogenic or non-pathogenic organisms. Especially if pathogenic organisms are used as a source of antigens, they may be inactivated or killed prior to use by heat inactivation, autoclaving or any other means known to the art. Naturally occurring peptides may furthermore be mutated by the substitution, addition or deletion of natural or non-natural amino acid residues. Especially substitutions may be benign, meaning that an amino acid residue is exchanged for an amino acid residue of the same type such as the original. As an example: The amino acids Asp, Glu, Lys, Arg, His, Asn, Gln, Ser, Thr, Tyr, and Cys all have polar chains and thus exchanging one of these for another would constitute a benign substitution. Examples of various groups of amino acids that are related by the nature of their side chains apart from the abovementioned are: Amino acids having non-polar side chains (Gly, Ala, Val, Leu, Ile, Phe, Trp, Pro, and Met), amino acids having aliphatic side chains (Gly, Ala Val, Leu, Ile), amino acids having cyclic side chains (Phe, Tyr, Trp, His, Pro), amino acids having aromatic side chains (Phe, Tyr, Trp), amino acids having acidic side chains (Asp, Glu), amino acids having basic side chains (Lys, Arg, His), amino acids having amide side chains (Asn, Gln), amino acids having hydroxy side chains (Ser, Thr), amino acids having sulphor-containing side chains (Cys, Met), neutral, weakly hydrophobic amino acids (Pro, Ala, Gly, Ser, Thr), hydrophilic, acidic amino acids (Gln, Asn, Glu, Asp), and hydrophobic amino acids (Leu, Ile, Val). Substitutions may also occur outside of any of the above defined groups. The resulting peptide may be referred to as a mutated peptide.

The moieties of the present invention may furthermore be modified in several ways. These modifications are often referred to as post translational modifications, as the modifications take place after the translation of the mRNA into protein within a cell. All of the mentioned modifications may be performed synthetically on any of the moieties of the invention. The modifications of the present invention include but are not limited to modifications involving the addition of functional group such as: acetylation (the addition of an acetyl group, usually at the N-terminus of the protein), alkylation (the addition of an alkyl group (e.g. methyl, ethyl), especially methylation (the addition of a methyl group, usually at lysine or arginine residues), biotinylation (acylation of conserved lysine residues with a biotin appendage), glutamylation (covalent linkage of glutamic acid residues to tubulin and some other proteins), glycylation (covalent linkage of one to more than 40 glycine residues to the tubulin C-terminal tail), glycosylation (the addition of a glycosyl group typically to either asparagine, hydroxylysine, serine, or threonine, resulting in a glycoprotein) isoprenylation (the addition of an isoprenoid group e.g. farnesol and geranylgeraniol), lipoylation (attachment of a lipoate functionality), phosphopantetheinylation (the addition of a 4′-phosphopantetheinyl moiety from coenzyme A, as in fatty acid, polyketide, non-ribosomal peptide and leucine biosynthesis), phosphorylation (the addition of a phosphate group to any residue, but typically to serine, tyrosine, threonine or histidine), sulfation (the addition of a sulfate group to a tyrosine), selenation and C-terminal amidation.

Preferably, the moieties of the present invention are modified by phosphorylation, sulfation, glycosylation, methylation, and/or acetylation. Any moiety may thus be modified at least once with any of the above mentioned modifications. And any peptide or peptide-like compound may comprise none, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 20 or more modifications or any number herein between or above.

Other modifications may be the addition of other proteins or peptides such as ISGylation (the covalent linkage to the ISG15 protein (Interferon-Stimulated Gene 15)), SUMOylation (the covalent linkage to the SUMO protein (Small Ubiquitin-related MOdifier)), ubiquitination (the covalent linkage to the protein ubiquitin), or may involve a change of the chemical nature of amino acids, such as citrullination/deimination (the conversion of arginine to citrulline), deamidation (the conversion of glutamine to glutamic acid or asparagine to aspartic acid) or modifications may involve structural changes such as disulfide bridges (the covalent linkage of two cysteine amino acids), proteolytic cleavage (cleavage of a protein at a peptide bond). Preferably, the moieties of the present invention are modified by ubiquitination, deamidation or the formation of disulfide bridges. These modifications may be singularly appearing or repeatedly appearing together with any of the above mentioned modifications.

By peptide is meant any plurality of individual moieties as are comprised in the above definition, occasionally these will be referred to as peptide-like compounds in the present text. Thus any type of bond may link the individual moieties of above, not only peptide bonds. Examples of bonds linking moieties of the present invention are: peptide bonds, sulfonamide bonds, ester bonds, saccharide bonds, carbamate bonds, carbonate bonds, urea bonds, phosphonate bonds, urethane bonds, azatide bonds, peptoid bonds, ether bonds, ethoxy bonds, thioether bonds, single carbon bonds, double carbon bonds, triple carbon bonds, disulfide bonds, sulfide bonds, phosphodiester bonds, oxime bonds, imine bonds and imide bonds. Any of the bonds of the above may be used as the only type of bond within the peptide, or two or more such as three or more different types of bonds may be comprised within a peptide-like compound. Preferably, the bonds connecting the moieties of the invention are peptide bonds, imine bonds and imide bonds, and most preferably peptide bonds.

The peptides of the present invention may furthermore comprise various domains such as an α-peptide domain, a β-peptide domain, a γ-peptide domain, a w-peptide domain, a mono-, di- and tri-substituted α-peptide domain, a mono-, di- and tri-substituted β-peptide domain, a mono-, di- and tri-substituted γ-peptide domain, a mono-, di- and tri-substituted w-peptide domain, a peptide domain wherein the amino acid residues are in the L-form, a peptide domain wherein the amino acid residues are in the D-form, a peptide domain wherein the amino acid residues are both in the L-form and in the D-form, a vinylogous peptide domain, a glyco-peptide domain, a vinylogous sulfonamide peptide domain, a polysulfonamide domain, a conjugated peptide domain and a conjugated peptide domain comprising one or more functional group(s), such as one or more prosthetic group(s).

Antigens according to the present invention are defined as antigens with a length in the range of from 5 moieties as defined in the above to preferably less than 1000 moieties. The length of the antigens may thus be at least 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 moieties or amino acid residues long, or at least 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, 600, 650, 700, 750, 800, 850, 900, 950 or 1000 moieties in length. Preferably, the antigens are between 5 and 500 moieties in length or any interval comprised therein, such as between, 5 and 400, 5 and 300, 5 and 200, 5 and 100, 5 and 50, 5 and 45, 5 and 40, 5 and 35, 5 and 30, 5 and 25, 5 and 24, 5 and 23, 5 and 22, 5 and 21, 5 and 20, 5 and 19, 5 and 18, 5 and 17, 5 and 16, 5 and 15, 5 and 14, 5 and 13, 5 and 12, 5 and 11, 5 and 10, 5 and 9, 5 and 8, 5 and 7 or 6 moieties in length. The antigens may furthermore be of a length in the range of from 10 to 20, 10 to 30, 10 to 40, 10 to 50, 10 to 60, 10 to 70, 10 to 80, 10 to 90, 10 to 100, 10 to 125, 10 to 150, 10 to 175, 10 to 200 moieties in length or from 15 to 20, 15 to 25, 15 to 30, 15 to 40, 15 to 50, 15 to 60, 15 to 70, 15 to 80, 15 to 90, 15 to 100, 15 to 125, 15 to 150, 15 to 175, 15 to 200, 20 to 50, 20 to 75, 20 to 100, 20 to 200, 20 to 250, 20 to 300, 20 to 350, 20 to 400 or more in length.

The antigens of the present invention are typically comprised in a library of antigens, meaning that there are more than 2 antigens present. The antigens according to the invention can be a mix of antigens and/or peptides of different lengths, i.e. there may be short antigens and/or peptides present with a length as short as 5 moieties as well as longer antigens. Some or all of the antigens/peptides may also be in form of peptides/polypeptides or proteins being either denatured or in their naturally folded form. It follows that proteins can be obtained from either a natural source or they can be recombinantly produced and subsequently purified.

Antigens according to the present invention are preferably of peptide origin with a length of at least 5 amino acids, and may be derived either from natural sources, produced by recombinant methods, or synthesized artificially—or any mixtures thereof. The antigens used for immunisation in connection with the present invention may comprise or be substantially free from e.g. contaminating cellular debris such as cellular material including cell membranes, nucleic acids, etc.

Carriers

Conjugation to a carrier is important because antigens, peptides and peptide-like compounds may be small molecules and small molecules alone do not tend to be immunogenic, thus possibly eliciting a weak immune response. The carrier typically contains many epitopes that stimulate T-helper cells, which help induce the B-cell response.

The carrier may be present independently of an adjuvant (please see in the below). The purpose of conjugation and/or co-immunization of an antigen/immunogenic determinant and a carrier can be e.g. to increase the molecular weight of the antigen in order to increase the activity or immunogenicity of the determinant, to confer stability to the determinant, to increase the biological activity of the determinant, or to increase its serum half-life. The carrier protein may be any conventional carrier including any protein suitable for presenting immunogenic determinants. Conventional carrier proteins include, but are not limited to, keyhole limpet hemocyanin, serum proteins such as transferrin, bovine serum albumin, or human serum albumin, an ovalbumin, immunoglobulins, or hormones, such as insulin.

While any suitable pharmaceutical carrier known to those of ordinary skill in the art may be employed in the immunogenic and pharmaceutical compositions of this invention, the type of pharmaceutical carrier will vary depending on the mode of administration and whether a sustained release administration is desired. For parenteral administration, such as subcutaneous injection, the pharmaceutical carrier may e.g. comprise water, saline, alcohol, fat, a wax or a buffer. For oral administration, any of the above pharmaceutical carriers or a solid pharmaceutical carrier, such as mannitol, lactose, starch, magnesium stearate, sodium saccharine, talcum, cellulose, glucose, sucrose, and magnesium carbonate, may be employed. Biodegradable microspheres (e.g., polylactic galactide) may also be employed as pharmaceutical carriers for the pharmaceutical compositions of this invention. Suitable biodegradable microspheres are disclosed, for example, in U.S. Pat. No. 4,897,268 and U.S. Pat. No. 5,075,109.

The antigen may be encapsulated within the biodegradable microsphere or associated with the surface of the microsphere.

Antigens within the scope of the present invention could be conjugated by any method known to the person skilled in the art. For example they could be conjugated by a physical association generated for example by the formation of a chemical bond, such as for example a covalent bond, formed between compounds to be conjugated. Compounds could be conjugated for example by an oxidative induced cross-link, such as mild oxidative induced cross-link catalyzed by long-time expo-sure to atmospheric air, such as an over-night exposure. Alternatively, compounds could be conjugated using a chemical cross-linking reagent. Examples of chemical cross-linking reagents are glutaraldehyde, charbodiimid or formaldehyde.

The present invention provides embodiments comprising one or more antigens according to the above which are non-conjugated, an immunogenic composition wherein said antigen is conjugated and an immunogenic composition wherein said antigens are a mixture of non-conjugated and conjugated antigens.

Many different carriers can be used for coupling to antigens, especially to synthetic peptides. The most commonly selected carriers here fore are keyhole limpet hemacyanin (KLH) and bovine serum albumin (BSA). The higher immunogenicity of KLH often makes it the preferred choice. Another advantage of choosing KLH over BSA is that BSA is used as a blocking agent in many experimental assays. Because antisera raised against peptides conjugated to BSA will also contain antibodies to BSA, false positives may result. Although KLH is large and immunogenic, it may precipitate during cross-linking, making it difficult to handle in some cases. Ovalbumin (OVA) is another useful carrier protein. It is a good choice as a second carrier protein when verifying whether antibodies are specific for the peptide alone and not the carrier. Rabbit Serum Albumin (RSA) may be used when the antibody response to the carrier protein must be kept to a minimum. Rabbits immunised with RSA conjugate are less likely to raise antibodies to the carrier, as the RSA is recognized as “self.” If the RSA conjugate were injected into another host, the protein would not be recognized as self. The same principle, of course, applies when immunising with chicken-derived carriers in chicken. An example of a chicken derived carrier is CSA (Chicken Serum Albumin). By using CSA (Chicken Serum Albumin) or beads an immune response against the carrier may be avoided, thereby optimizing the productivity of the chicken immune response. It is important to recognize that the immune system reacts to the peptide-protein carrier as a whole and that there will be a portion of response directed against the conjugated peptide as well as the linker and the carrier. When screening by ELISA it is advisable to use a peptide conjugate prepared using a different carrier. This is not necessary if performing ELISA assays where the plates are coated directly with unconjugated peptide. Thus examples of carriers include, but are not limited to: BSA, CSA, SA, KLH, Beads or other carrier-systems. Suitable carriers will be of protein origin in most cases. In some cases however, the carrier may be of non-protein origin such as e.g. polymers comprising carbohydrates, etc. Preferably either CSA or beads are used to avoid immune response against the carrier.

It is an aspect of the present invention to use the carrier KLH.

The coupling can be made by glutaraldehyde, MBS or other coupling methods. Glutaraldehyde couples between free amino groups (—NH2) and cysteine. The ratio between peptide and carrier has to be exact to avoid over-coupling. By decreasing the pH to a value lower than the pK value of the amino acids coupling to the side chains is avoided. Correction has to be made for sequences containing cysteine.

It may not be necessary to conjugate relatively large antigens peptides with a carrier in order to obtain an immune response. Antigens/peptides with a length of at least 50 moieties/amino acids and more, preferably with a length of at least 100 moieties or at least 150 moieties may not need carrier conjugation in order to function as immunogens in the present invention. It is however advisable to conjugate all antigens with carrier molecules disregard the size of the antigen/the antigens.

Antigen Library

It is an object of the present invention that the plurality of avian species each is immunized with a plurality of antigens, herein referred to as an antigen library. The antigens of the library may or may not be coupled to a carrier as described in the above. The average numbers of antigens within such a library is in the range of from 2 to 100000.

In another aspect of the present invention polyclonal antibodies comprising antigen specific antibodies are obtained, by immunising a vertebrate animal with a composition comprising about 15 or more different peptide antigens, said peptides being conjugated with a carrier and having a length of at least 6 amino acids, and an adjuvant, collecting polyclonal antibodies from the animal, wherein a fraction of about 1% or more shows reactivity towards the antigens used for immunisation.

It is an aspect of the present invention to use an animal that is reimmunised.

In an embodiment of the present invention antibodies are collected from said animal after a period of at least 14 days.

In one aspect of the invention the peptide antigens is a peptide library obtainable by randomly synthesizing peptides with a length of at least 6 amino acids.

It is an aspect of the present invention to use an antigen mix comprising peptides with different lengths.

An antigen library may be a peptide library constructed randomly by solid-phase-synthesis with controlled coupling to either tert-butyl-oxy-carbonyl (BOC) groups or Fluorenyl-metoxy-carbonyl (FMOC). Instead of producing the single peptides individually, they are all produced simultaneously. Peptides will be produced to cover all possible domains. This means that modified moieties such as glycosylated and phosphorylated moieties/amino acids also are represented. Employing the random coupling between the amino acids the peptides are produced fast, cheap and divided into smaller groups. A smaller group refers as an example to 10.000 antigens. A group can be generated by excluding certain moieties or modifications from the reaction.

A way of carrying out the present invention is to synthesize a peptide library with peptides of similar lengths covering all the possible combinations of the moieties disclosed in the above. Peptide synthesis may take place in solution or on a solid phase. A peptide library with peptides of a length of e.g. 6 of the 20 most often naturally occurring amino acids will thus in theory have 20⁶ different ways of combining the amino acids, and thus up to 20⁶ different peptides. The peptide library may also be a library comprising e.g. a specific fraction of the amino acid sequence from a number of different proteins with known sequences. The peptides must have lengths of at least 5 amino acids in order to be able to bind to the hypervariable loops of the Fab fragment of the antibody.

It follows that peptide libraries may also be prepared using more or less than the 20 most often occurring natural amino acids—in which case of course the theoretical number of different combinations will vary accordingly. Any of the above defined antigens comprising any of the above defined moieties with any of the above defined modifications may be combined to form part of the antigen library. Any of the resulting combinations may or may not be coupled to a carrier according to the above prior to immunization (with or without further mixing with an adjuvant).

Host

The host is the animal or individual used for the generation of the antibody libraries according to the present invention. The host may be an animal from the vertebrate phyla. Preferred animals are animals from either the mammalian or the avian orders. Avian animals are particularly preferred. Birds from the Galliformes order are most preferred, thus in one embodiment of the present invention the vertebrate animal is of the species Gallus gallus domestica.

The Galliformes order of birds includes grouse, ptarmigan, capercaillie, partridges, pheasants, quails, turkeys and peacocks. These are mainly grain-eating, heavy-bodied, ground-nesting birds, capable of only short, rapid flights. The cocks are usually more colourful than the hens. A preferred bird according to the present invention is a Gallus gallus domestica either in the adult stage or as a chicken at the age of at least 17-19 weeks. Especially preferred are the females of any of the above mentioned avian species. Birds used for immunisation should have an age of at least 17 weeks, preferably at least 19 weeks.

The hen of Gallus gallus domestica is ideal because it can produce about 1500 mg antibodies per month (about 50-100 mg antibodies per egg (AOEA 24: 925-934, 1996). In fact, antibodies can be obtained in a non-invasive manner from the chicken during the entire egg-laying period. Usually, about 2-10% of the antibodies are antigen specific (AOEA 24: 925-934, 1996). The percentage of antigen specific antibodies may be even higher as a response to immunization with a multitude of antigens.

It is an important aspect of the present invention to immunize a plurality of hosts for the production of antibody libraries. Therefore, the number of host, especially avian organisms, immunized is about 1000, such as about 2000, for example about 3000, such as about 4000, for example about 5000, such as about 5500, for example about 6000, such as about 6500, for example about 7000, such as about 75000, for example about 8000, such as about 8500, for example about 9000, such as about 9500, for example about 10000, such as about 10500, for example about 11000, such as about 115000, for example about 12000, such as about 12500, for example about 13000, such as about 13500, for example about 14000, such as about 14500, for example about 15000, such as about 16000, for example about 17000, such as about 18000, for example about 19000, such as about 20000, for example about 21000, such as about 22000, for example about 23000, such as about 24000, for example about 25000, such as about 26000, for example about 27000, such as about 28000, for example about 29000, such as about 30000, for example about 31000, such as about 32000, for example about 33000, such as about 34000, for example about 35000, such as about 36000, for example about 37000, such as about 38000, for example about 39000, such as about 40000, for example about 41000, such as about 42000, for example about 43000, such as about 44000, for example about 45000, such as about 50000.

Preferably, any number of hosts from 10 to 100000 is immunized. More preferably the number of hosts is between 100 and 50000, such as between 200 and 40000, 300 and 10000, 400 and 9000, 500 and 8000, 600 and 7000, 800 and 6000, 900 and 5500, 1000 and 5000.

Adjuvants

Adjuvants, also known as pharmaceutical carriers, or functional equivalents hereof may be included in the immunization solution/vaccine composition to enhance the specific immune response. Thus, it is particular important to identify an adjuvant that when combined with the antigen(s) results in an immunization composition capable of inducing a strong specific immunological response. Functionally equivalent carriers are capable of presenting the same immunogenic determinant in essentially the same steric conformation when used under similar conditions. Functionally equivalent adjuvants are capable of providing similar increases in the efficacy of the composition when used under similar conditions.

Preferably, the immunogenic compositions (composition of the present invention) comprise potent, nontoxic adjuvants that will enhance and/or modulate the immunogenicity of immunogenic determinants including antigenic determinants including haptenic determinants represent one group of preferred adjuvants. In addition, such adjuvants preferably also elicit an earlier, more potent, or more prolonged immune response. Such an adjuvant would also be useful in cases where an antigen supply is limited or is costly to produce.

A large number of adjuvants have been described and used for the generation of antibodies in laboratory animals, such as mouse, rats, rabbits and chickens. In such setting the tolerance of side effect is rather high as the main aim is to obtain a strong antibody response.

An embodiment of the present invention relates to an immunization composition comprising an adjuvant. In a preferred embodiment the vaccine composition is suitable for administration to an avian subject, thus a preferred adjuvant is suitable for administration to a chicken or hen as defined in the above.

The choice of adjuvant may further be selected by its ability to stimulate the type of immune response desired, B-cell or/and T-cell activation and the vaccine composition may be formulated to optimize distribution and presentation to the relevant lymphatic tissues.

Adjuvants pertaining to the present invention may be grouped according to their origin, be it mineral, bacterial, plant, synthetic, or host product. The first group under this classification is the mineral adjuvants, such as aluminum compounds. Antigens precipitated with aluminum salts or antigens mixed with or adsorbed to performed aluminum compounds have been used extensively to augment immune responses in animals and humans. Aluminium particles have been demonstrated in regional lymph nodes of rabbits seven days following immunization, and it may be that another significant function is to direct antigen to T cell containing areas in the nodes themselves. Adjuvant potency has been shown to correlate with intimation of the draining lymph nodes. While many studies have confirmed that antigens administered with aluminium salts lead to increased humoral immunity, cell mediated immunity appears to be only slightly increased, as measured by delayed-type hypersensitivity. Aluminium hydroxide has also been described as activating the complement pathway. This mechanism may play a role in the local inflammatory response as well as immunoglobulin production and B cell memory. Furthermore, aluminum hydroxide can protect the antigen from rapid catabolism. Primarily because of their excellent record of safety, aluminum compounds are presently the only adjuvants used in humans.

Another large group of adjuvants is those of bacterial origin. Adjuvants with bacterial origins can be purified and synthesized (e.g. muramyl dipeptides, lipid A) and host mediators have been cloned (Interleukin 1 and 2). The last decade has brought significant progress in the chemical purification of several adjuvants of active components of bacterial origin: Bordetella pertussis, Mycobacterium tuberculosis, lipopoly-saccharide, Freund's Complete Adjuvant (FCA) and Freund's Incomplete Adjuvant (Difco Laboratories, Detroit, Mich.) and Merck Adjuvant 65 (Merck and Company, Inc., Rahway, N.J.). Additionally suitable adjuvants in accordance with the present invention are e.g. Titermax Classical adjuvant (SIGMA-ALDRICH), ISCOMS, Quil A, ALUN, see U.S. Pat. Nos. 58,767 and 5,554,372, Lipid A derivatives, choleratoxin derivatives, HSP derivatives, LPS derivatives, synthetic peptide matrixes, GMDP, and other as well as combined with immunostimulants (U.S. Pat. No. 5,876,735).

B. pertussis is of interest as an adjuvant in the context of the present invention due to its ability to modulate cell-mediated immunity through action on T-lymphocyte populations. For lipopolysaccharide and Freund's Complete Adjuvant, adjuvant active moieties have been identified and synthesized which permit study of structure-function relationships. These are also considered for inclusion in immunogenic compositions according to the present invention.

Lipopolysaccharide and its various derivatives, including lipid A, have been found to be powerful adjuvants in combination with liposomes or other lipid emulsions. It is not yet certain whether derivatives with sufficiently low toxicity for general use in humans can be produced. Freund's Complete Adjuvant is the standard in most experimental studies.

Mineral oil may be added to the immunogenic composition in order to protect the antigen from rapid catabolism.

Many other types of materials can be used as adjuvants in immunogenic compositions according to the present invention. They include plant products such as saponin, animal products such as chitin and numerous synthetic chemicals.

Adjuvants according to the present invention can also been categorized by their proposed mechanisms of action. This type of classification is necessarily somewhat arbitrary because most adjuvants appear to function by more than one mechanism. Adjuvants may act through antigen localization and delivery, or by direct effects on cells making up the immune system, such as macrophages and lymphocytes. Another mechanism by which adjuvants according to the invention enhance the immune response is by creation of an antigen depot. This appears to contribute to the adjuvant activity of aluminum compounds, oil emulsions, liposomes, and synthetic polymers. The adjuvant activity of lipopolysaccharides and muramyl dipeptides appears to be mainly mediated through activation of the macrophage, whereas B. pertussis affects both macrophages and lymphocytes. Further examples of adjuvants that may be useful when incorporated into immunogenic compositions according to the present invention are described in U.S. Pat. No. 5,554,372.

Useful adjuvants useful may thus be mineral salts, such as aluminium hydroxide and aluminium or calcium phosphates gels, oil emulsions and surfactant based formulations such as MF59 (microfluidised detergent stabilised oil in water emulsion), QS21 (purified saponin), AS02 (SBAS2, oil-in-water emulsion+monophosphoryl lipid A (MPL)+QS21), Montanide ISA 51 and ISA-720 (stabilised water in oil emulsion), Adjuvant 65 (containing peanut oil, mannide monooleate and aluminum monostearate), RIBI ImmunoChem Research Inc., Hamilton, Utah), particulate adjuvants, such as virosomes (unilamellar liposomal cehicles incorporating influenza haemagglutinin), AS04 (Al salt with MPL), ISCOMS (structured complex of saponins and lipids (such as cholesterol), polyactide co-glycolide (PLG), microbial derivatives (natural and synthetic) such as monophosphoryl lipid A (MPL), Detox (MPL+M. Phlei cell wall skeleton), AGP (RC-529 (synthetic acylated monosaccharide)), DC_chol (lipoidal immunostimulators able to self organise into liposomes), OM-174 (lipid A derivative), CpG motifs (synthetic oligonucleotides containing immunostimulatory CpG motifs), modified bacterial toxins, LT and CT, with non-toxic adjuvant effects, Endogenous human immunomodulators, e.g., hGM-CSF or hIL-12 or Immudaptin (C3d tandem array), inert vehicles such as gold particles. Additional examples of adjuvants comprise: Immunostimulatory oil emulsions (for example, water-in-oil, oil-in-water, water-in-oil-in-water such as e.g. Freund's incomplete adjuvant such as Montainde®, Specol, mineral salts such e.g. as Al(OH)₃, AIPO₄, microbial products, Saponins such as Qual A, synthetic products, as well as adjuvant formulations, and immune stimulatory complexes (ISCOMs) and cytokines, heat-inactivated bacteria/components, nanobeads, LPS, LTA. A list of other commonly used adjuvants is disclosed on pages 6-8 in WO 03089471, the list being hereby incorporated by reference.

Immunogenic compositions according to the invention may also contain diluents such as buffers, antioxidants such as ascorbic acid, low molecular weight (less than about 10 residues) polypeptides, proteins, amino acids, carbohydrates including glucose, sucrose or dextrins, chelating agents such as EDTA, glutathione and other stabilizers and excipients. Neutral buffered saline or saline mixed with non-specific serum albumin are exemplary appropriate diluents. Preferably, the compostions are formulated as a lyophilizate using appropriate excipient solutions (e.g., sucrose) as diluents.

The immunogenic compositions of the present invention may furthermore comprise pharmaceutical carriers. Suitable carriers are typically large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers, lipid aggregates (such as oil droplets or liposomes), and inactive virus particles. Such carriers are well known to those of ordinary skill in the art. Additionally, these carriers may function as immunostimulating agents (“adjuvants”). Immunisation of the animal may be carried out with adjuvants and/or pharmaceutical carriers. An adjuvant is any substance that enhances the immune response to an antigen with which it is mixed. The antigen may also be mixed with two or more different adjuvants prior to immunisation.

It is an aspect of the present invention to utilize the adjuvant Specol.

Adjuvants are generally included in the immunogenic compositions in an amount according to the instructions of the manufacturer. If the adjuvant is Specol an amount of e.g. 1:1 compared to the antigen/carrier mixture or antigen mixture alone may be added to the immunogenic composition.

Preferably, the adjuvants of the present invention are Freunds complete adjuvant, Freunds incomplete adjuvant, Specol, Titermax Gold, Alhydrogel, Gerbu Adjuvant 100, Diluvac Forte and Super Adjuvant as defined in the Examples. More preferably, the adjuvants are Freunds complete adjuvant, Freunds incomplete adjuvant, Specol, Titermax Gold, and Super Adjuvant. With these preferred adjuvants, antibodies may be harvested after only about two weeks, instead after three to six weeks.

Method of Immunization

Immunogenic compositions according to the invention may be administered to a host in effective amounts resulting in the optimum production of antibodies. The effective amount may vary according to a variety of factors such as the host's condition, weight, and age. Other factors include the mode of administration.

The immunogenic compositions may be provided to the individual by a variety of routes such as subcutaneous, topical, oral and intramuscular. Administration of pharmaceutical compositions is accomplished orally or parenterally. Methods of parenteral delivery include topical, intra-arterial (directly to the tissue), intramuscular, subcutaneous, intramedullary, intrathecal, intraventricular, intravenous, intraperitoneal, or intranasal administration. The present invention also has the objective of providing suitable topical, oral, systemic and parenteral pharmaceutical formulations for use in the methods of prophylaxis and treatment of the vaccine composition.

For example, the immunogenic compositions can be administered in such oral dosage forms as tablets, capsules (each including timed release and sustained release formulations), pills, powders, granules, elixirs, tinctures, solutions, suspensions, syrups and emulsions, or by injection. Likewise, they may also be administered in intravenous (both bolus and infusion), intraperitoneal, subcutaneous, topical with or without occlusion, or intramuscular form, all using forms well known to those of ordinary skill in the pharmaceutical arts. An effective but non-toxic amount of the vaccine, comprising any of the herein described compounds can be employed as a prophylactic or therapeutic agent. Also any and all conventional dosage forms that are known in the art to be appropriate for formulating injectable immunogenic peptide composition are encompassed, such as lyophilised forms and solutions, suspensions or emulsion forms containing, if required, conventional pharmaceutically acceptable carriers, diluents, preservatives, adjuvants, buffer components, etc.

Preferred modes of administration of the immunogenic composition according to the invention include, but are not limited to systemic administration, such as intravenous or subcutaneous administration, intradermal administration, intramuscular administration, intranasal administration, oral administration, rectal administration, vaginal administration, pulmonary administration and generally any form of mucosal administration. Furthermore, it is within the scope of the present invention that the means for any of the administration forms mentioned in the herein are included in the present invention.

Preferably, the method of administration involves injection. The animals may be immunised with the antigens intramuscularly, intrasplenically, intravenously, intraperitoneally, intradermally or subcutaneously or by any other suitable means. Most preferably the chickens kept under field conditions are immunized in the breast musculature with a pistol. This spares the chicken for a slow and stressing immunization. In the laboratory, chickens most preferably are vaccinated subcutaneously in the neck.

An immunogenic composition according to the present invention can be administered once, or any number of times such as two, three, four or five times. Administering the composition more than once has the effect of boosting the resulting immune response. The composition can further be boosted by administering it in a form or body part different from the previous administration. The booster shot is either a homologous or a heterologous booster shot. A homologous booster shot is a where the first and subsequent administrations comprise the same compositions and more specifically the same antigens and adjuvants. A heterologous booster shot is where identical antigen libraries are comprised in different compositions, i.e. different adjuvants and carriers.

The total number of immunisations will depend upon the type and dose of the antigen, as well as on the particular adjuvant and carrier employed. In a preferred embodiment, at least two administrations are given, such as 3, 4, 5, 6, 7, 8, 9, 10 or more administrations. If the antibody titres begin to decrease, further booster immunisations can be given.

It falls within the scope of the present invention that the means and modes of administration of the immunogenic composition are adapted to the host. A preferred recipient of the vaccine is an avian, such as a chicken of the species Gallus gallus.

An embodiment of the present invention includes an immunogenic composition further comprising a second active ingredient. The second active ingredient is selected from, but not limited the group of antibiotics, chemotherapeutics, anti-allergenics, cytokines, complement factors and co-stimulatory molecules of the immune system, any compound or supplement which may be of benefit to the host organism.

The total amount of peptide employed for each immunisation may likewise vary. Amounts of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, or 500 μg are preferably used in a single immunisation. But amounts of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75, 100, 125, 150, 175, 200, 250, or 500 mg may also be used in a single immunisation.

The method of any of claims 1 to 25 further comprising administering said different antigens to said avian organism(s) in the presence of one or more carrier(s) covalently or non-covalently attached to at least some of said antigens.

The amount of different peptide antigens used for immunisation of the animal is at least 15. As the aim of the present invention is to provide tools for rapidly isolating antigen specific antibodies, it is advantageous to immunise with even more antigens, as the likelihood thus increases of obtaining antibodies with specificity to most antigens. It is therefore preferable to immunise with at least about 25, 50, 51, 60, 70, 80, 90, 100, 150, 200, 250, 500, 1000, 5000, 10000, 50000, 100000, 500000, 1000000, or 5000000 different antigens. It is most preferable to immunise with a synthetically synthesized peptide library comprising, in theory, 20⁶ or more different peptide combinations.

Antibody Library

The present invention relates to a method for generating an antibody library i.e. a plurality of different IgY antibodies, said method comprising the step of immunizing each of a plurality of avian organisms of the same or different species with a composition comprising a plurality of different antigens, thereby generating a plurality of different IgY antibodies

A preferred way of obtaining an antibody library is by immunizing with a peptide library obtainable by synthesizing peptides with a length of at least 5 amino acids. Likewise, the peptide antigen may also be a mix of peptides with different lengths.

A library of antibodies according to the present invention can be obtained by immunising a single animal with an antigen library, for example a randomly generated peptide library. A randomly generated peptide library will in general stimulate an antibody response comprising antibodies with binding capability of (in theory) any antigen.

According to the present invention an antibody can be termed antigen specific if e.g. antigen:antibody binding can be demonstrated in an assay as disclosed in the examples, where antigen is linked to a carrier in the presence of PBS and antibodies are likewise suspended in a PBS buffer.

According to the present invention, at least about 1% of the antibodies obtained subsequent to immunisation show specificity to the antigens used for immunisation. If less than 1% of the antibodies show specificity to the antigens, antibodies may e.g. have been harvested too soon after immunisation, insufficient amounts of antigen have been employed, or inefficient amounts of adjuvants have been employed. More preferably, at least about 2, 3, 4, or 5% of the antibodies are antigens specific. Most preferably, at least about 6, 7, 8, 9, or 10% of the antibodies are specific. And most preferably about 20-30% of the antibodies are antigen specific.

Conditions suitable for an antigen:antibody binding to take place: such conditions are well known in the art. In the Examples, PBS buffer is employed.

It is known in the art how to purify antibodies from egg yolk. Please see the examples for methods hereof. Of additional methods hereof include the use of Dextran, Lithium sulfat, Triton, CA, Xan as precipitation agents or the use of the method of water dilution. All precipitated and thus harvested antibodies are pooled into the antibody library.

Harvest of Antibodies

The antigen that one wishes to have a specific antibody against (i.e. with binding specificity towards) is synthesized an coupled/linked to an epoxy coated pole. The pole is the transferred into the antibody library storage device, wherein an interaction between the antigen(s) and antibodies will take place. The pole is removed from the library and by varying the strength (lowering the pH) of the elution solution or by sonication at varying strengths, the bound antibodies can be eluted according to their binding affinity, which may be termed: low medium and high. The antigen is covalently bound to the pole, and the bound to the antibody by ion-bonds (hydrogen bonds aso.), wherefore the bond between the antigen and antibody is broken first. The fluid comprising the antibodies is dialyzed against PBS, and any reduction in the volume is corrected. The desired antibody, it being of high, medium or low affinity according to ones needs, is now available as an isolated product. Any unwanted antibodies may be returned to the library.

In an embodiment of the present invention antigen specific antibodies are isolated from an antibody pool generated as described herein above, wherein the method comprises the steps of immobilising the antigen, contacting the antibody pool with the immobilized antigen under conditions suitable for an antigen:antibody binding to take place, removing unbound antibody, and recovering antigen specific antibodies.

In another embodiment of the present invention the antigen specific antibodies described herein above are recovered using acidic conditions.

It is an object of the present invention to immobilize the antigen on a CNBr carrier, such that the peptide or antigen that one wishes to have a specific antibody against is synthesised and coupled to sepharose-CNBr beads. The beads are then transferred to a column and the antibody library or a fraction hereof will be run over the column. Antibodies will bind to the antigens bound to the column matrix. By eluting the antibodies with decreasing values of pH, antibodies of first low, subsequently medium and finally high affinity will be eluted from the column.

The antibody:antigen bound beads may subsequently (after or before elution with varying pH strengths) by transferred to a flow chamber. In the flow chamber sound pulses (sonication) will release the most tightly bound antibodies from the antigens. The flowthrough comprising the thus released antibodies is dried and dialysed against PBS.

Any superfluous antigen/peptide is stored for refilling the library. Refilling the library may be by immunizing a number of hosts with the particular antigen/peptide and adding the thus generated antibodies to the antibody library.

By using different elution conditions, the method allows an approximate quantification of the binding affinity of the monoclonal antibody for its binding partner. Elution agents that may be used include chaotropic agents such as guanidine hydrochloride or urea at concentrations between 10 μM and 8 M or ethylene glycol in an aqueous solution of 0.01% to 100% w/v. Elutions may also be carried out using aqueous or non-aqueous solutions of glycine. Elutions may be carried out using aqueous or non aqueous solutions of triethylamine between 1 μM and a saturated solution, preferably 100 mM, at a pH of between pH 8 and pH 13, preferably pH 11.5.

Storage and Shipping of Antibody Libraries and Harvested Antibodies

Ideally, the antibodies are pooled and stored until a time where it is desired to isolate antigen specific antibodies. Antibodies can be stored at subzero degrees (e.g. liquid nitrogen, −70° C., or −20° C.). However, if the library is used for frequent isolation of antigen specific antibodies, it may be preferable to avoid freezing by storing the library at temperatures of about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10° C. Even though antibodies tend to be stable, repeated freeze/thaw circles may result in some degree of protein denaturation of the antibodies.

In an embodiment of the present invention the antibodies generated as described herein above are stored in presence of one or more additives selected from the group consisting of: antibiotics, anti-fungal compounds, and buffer.

In another embodiment of the present invention the antibodies generated as described herein above are stored at a temperature of about 0-100° C.

Antibodies according to the invention may furthermore be stored in the presence of one or more additives such as: antibiotics, anti-fungal compounds, antifreeze (e.g. glycerol), and buffer solutions. A preferred additive is NaN₃—preferably 0.1% NaN₃ in PBS. Antibodies may even be stored at room temperature, preferably in the presence of preservatives, for relatively short period of times such as e.g. two weeks or less, preferably one week or less. This might be convenient e.g. in case of transport of antibodies via shipping, mailing, etc.

In a preferred embodiment, antibodies are collected from the animal after a period of at least 14 days, since this period of time is usually required to induce a detectable immune response in e.g. a chicken subsequent to immunization.

Ideally, the antibodies are pooled and stored until a time where it is desired to isolate antigen specific antibodies. Antibodies can be stored at subzero degrees (e.g. liquid nitrogen, −70° C., or −20° C.). However, if the library is used for frequent isolation of antigen specific antibodies, it may be preferable to avoid freezing by storing the library at temperatures in a range of about 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10° C. Even though antibodies tend to be stable, repeated freeze/thaw circles may result in some degree of protein denaturation of the antibodies.

The present invention furthermore relates to antibodies obtainable by the methods herein.

The present invention furthermore relates to antibodies obtainable by the methods herein.

Additional Embodiments

Another central aspect of the present invention relates to the use of antibody libraries being specific to a multitude of antigens. In particular, the present invention thus relates to a method of isolating antigen specific antibodies, wherein the method comprises the following steps:

-   -   immobilizing the antigen,     -   contacting the antibody library with the immobilized antigen         under conditions suitable for an antigen:antibody binding to         take place,     -   removing unbound antibody, and     -   recovering antigen specific antibodies.

An antibody library obtained after immunizing an animal with a peptide library generated by random synthesis thus provides a unique possibility of isolating antibodies with specificity to an antigen within a very short period of time—in theory within few hours.

Various methods of immobilizing the antigen can be employed in connection with isolation of antigen specific antibodies. A preferred solid phase is CNBr carrier. A preferred coupling is Epoxy coupling, since this approach is relatively cheap. Ultrasound sonification or acidic conditions may e.g. be used for breaking the antigen:antibody binding in order to recover antigen specific antibodies. In general, various methods of coupling proteins to a carrier and subsequently breaking protein:protein interactions are well known in the art.

Finally, the present invention relates to antibodies obtainable by the methods herein. The bond between antigens and antibodies is dependent on hydrogen bonds, hydrophobic bonds, electrostatic forces, and van der Waals forces. These are all bonds of a weak, non-covalent nature, yet some associations between an antigen and an antibody can be quite strong. Accordingly, the affinity constant for antibody-antigen binding can span a wide range, extending from below 10⁵ mol⁻¹ to more than 10¹² mol⁻¹. Affinity constants are affected by temperature, pH and solvent. Apart from an affinity of an antibody for a ligand, the overall stability of an antibody-ligand complex is also determined by the valency of the antigen and antibody and the structural arrangement of the interacting parts.

Affinity constants can be determined for monoclonal antibodies, but not for polyclonal antibodies, as multiple bonds take place between polyclonal antibodies and their antigens.

Monoclonal antibodies can be raised by fusion of B lymphocytes with immortal cell cultures to produce hybridomas. Hybridomas will produce many copies of the exact same antibody—an essential feature in the development of antibodies for diagnostic applications. As monoclonal antibodies react with one epitope on the antigen, they are more vulnerable to the loss of epitope through chemical treatment of the antigen than are polyclonal antibodies. This can be offset by pooling two or more monoclonal antibodies to the same antigen.

The specificity of monoclonal antibodies makes them extremely efficient for binding of antigen within a mixture of related molecules, such as in the case of affinity purification.

Also, as compared to polyclonal antibodies, the homogeneity of monoclonal antibodies is very high. Accordingly, if experimental conditions are kept constant, results from monoclonal antibodies will be highly reproducible.

It is an object of the present invention to generate antibodies as described herein above.

In an embodiment of the present invention antibodies are obtained as described herein.

Use of Abs

In an embodiment of the present invention antibodies are generated and used as described herein.

It is furthermore an aspect of the present invention to use the antibodies generated or harvest or both by the methods described herein for the treatment of diseases causing diarrhea. However, antibodies can be used to fight all diseases caused by bacteria, viruses, parasites (uncertain), chemicals (uncertain) or other agents which crosses the stomach-colon (e.g. cystic fibrosis). The bacteria are hindered in proliferation and the severity and course of the disease is decrease by the antibodies. Due to the re-immunization system it will be possible to target all intern diseases as for example cancer, AIDS, cold etc. If open to the idea several diseases can theoretically be treated.

When it comes to pigs we show a special attention to the following agents causing diarrhea:

-   -   1. Clostridia     -   2. Cocciciosis     -   3. Colibacillosis (E. Coli)     -   4. PED     -   5. PRRS     -   6. Rotavirus     -   7. TGE

Additionally we show attention to the most widespread agent causing diarrhoea in human beings. To mention are: Camphylobachter jejuni, Salmonella, Shigella, E. Coli. However, still we do not have a complete list of the most lucrative diseases.

EXAMPLES Example 1 Synthesis of a Peptide Library

A library of peptides with a length of 6 amino acids and of 15 amino acids was synthesized using standard methods. The 20 most commonly occurring (excl. selenocysteine and pyrrolysine) natural amino acids were employed in each reaction and the library thus synthesized at least in theory comprises 20⁶ or 20¹⁵, respectively, different peptides.

Example 2 Antigen Coupling Method 1:

Peptides to be used as antigens are coupled to a carrier. In this method the peptide sequence must contain at least one cysteine residue or an NH2 group in order for the cross linking agent (MBS) to efficiently couple the peptides to the carrier protein Keyhole Limpet Hemocyanin (KLH). In this example, a cysteine residue was added to the peptides as the seventh residue before carrier conjugation.

Sephadex G-25 fine beads were swelled overnight in 5 ml buffer (0.1 M NaH2PO4 pH 6.0)/g of dry beads at room temperature. The swelled resin was washed 4 times using 0.1 M NaH2PO4 pH 6.0 and poured into a 130×20 mm column. The column was subsequently equilibrated with 15 ml of 0.1 M NaH2PO4 pH 6.0 and the resin was allowed to settle.

4 mg KLH was dissolved in 0.3 ml of 0.1 M NaH2PO4 pH 6.0. 1 mg m-Maleimidobenzoyl-N-Hydroxysuccinimide ester (MBS) in 150 μl of Dimethylformamide (DMF) was added drop-wise to the KLH solution under stirring. The KLH/DMF mixture was incubated at room temperature for 30 min on a rotating mixer.

1 ml of 0.1 M NaH2PO4 pH 6.0 was added to the KLH-MBS conjugate followed by thorough mixing. The mixture was subsequently loaded onto the Sephadex G-25 column. 0.1 M NaH2PO4 pH 6.0 was used as column buffer.

1 ml fractions were collected by gravity flow in 1.5 ml tubes. The fractions comprising the KLH-MBS conjugate (monitored at 280 nm) were pooled in a 15 ml conical tube.

200 μl of Dimethylformamide (DMF), 1 ml of peak fractions at 280 nm pH 6.0, and 5 mg of the cysteine-containing peptide were mixed.

The peptide solution was mixed with the KLH-MBS conjugate and incubated for 12 to 16 hr at room temperature on a rotating mixing wheel.

The KLH-MBS-peptide conjugate was dialyzed for 24 hr at 4° C. against 1 liter of PBS including two changes of buffer. Molecular weight cut off of the dialysis tube was 3,500.

Method 2:

By using Chicken Serum Albumin (CSA) or beads for coupling of the antigens an immune response against the carrier is avoided, thereby optimizing the productivity of the chicken immune response. The coupling between the peptides and the carrier is mediated by glutaraldehyde, which couples free amino groups (—NH2) and cysteines. The ratio between peptide and carrier has to be exact to avoid over-coupling. By decreasing the pH to a value lower than the pK value of the amino acid residues, coupling to the side chains of the amino acid residues is avoided. Corrections in this calculation have to be made for sequences containing cysteine.

-   -   1. 5 mg/ml of peptide in PBS (Phosphate Buffered Saline).     -   2. CSA carrier protein is added in the ratio of 1-2 mol of         peptide per 50 amino acids in the carrier. Mix by magnetic         stirring under ventilated conditions.     -   3. While stirring add 0.2% glutaraldehyde in PBS, at a ratio of         1 ml glutaraldehyde/PBS per 20 μmol peptide/protein solution.     -   4. Incubate 1 hour at room temperature.     -   5. Add 1 M glycerine in PBS, pH 7.2, to a final concentration of         200 mM. Stir for 1 hour.     -   6. Separate the peptide-carrier from unbound peptide by dialysis         against PBS. 4 changes of buffer each 2 hours.

Example 3 Immunization Method 1:

20 and 35 weeks old fowls of the “white Italian” race were immunized on day 0, 10, 20, 100 and 200. Blood samples and eggs were taken on day 0, 7, 14, 21, 28, 35, 42, 49 and antibody concentration (IgY) was measured using ELISA techniques (se in the below).

The composition used for each immunisation was: 10 μg KLH-peptide dissolved in 0.01 M NaCl buffer (pH 7.2) to a volume of 500 μl and 500 μl Specol to a total volume of 1 ml.

Method 2:

The chickens are immunized in the breast musculature with a pistol. The animals are immunized at day 1, 10 and subsequently every 4^(th) week. For each immunization one of the following compositions is used:

-   -   1. a minimum of 0.5 mg peptide-carrier mixed in the ratio of 1:1         to Freund's Incomplete Adjuvant diluted in PBS to 200     -   2. a minimum of 0.5 mg peptide-carrier mixed in the ratio of 1:1         to Super Adjuvant diluted in PBS to 200 μl (for the composition         of the Super Adjuvant, please see in the below).

Example 4 Testing of Super Adjuvant Components of the Adjuvant:

-   -   1. Specol: marcol 52®, Span 85®, Tween 85® (tested with positive         results)     -   2. Vitamin E     -   3. Al(OH)₃     -   4. Heat Shock Proteins     -   5. CpG-peptides     -   6. Heat-inactivated B. Pertussis     -   7. dsRNA

Experimental Design:

7 groups of 4 chickens are immunized with the following Adjuvant components:

1 2 3 4 5 6 7 Antigen Antigen Antigen Antigen Antigen Antigen Antigen Specol Specol Specol Specol Specol Specol Specol E-vitamin E-vitamin E-vitamin E-vitamin E-vitamin E-vitamin Al(OH)3 Al(OH)3 Al(OH)3 Al(OH)3 Al(OH)3 HSP HSP HSP HSP CpG CpG CpG B. Pertussis B. Pertussis Synthetic pl:C

Reagents:

-   -   1. PBS     -   2. Specol:         -   1. 8.1 ml Span 85® is mixed with 6.1 ml Tween 85®         -   2. 99 ml marcol 52® is mixed with 11 ml Span85®/Tween85®     -   3. Al(OH)₃: 8 mg/ml Al(OH)₃ solution is made (5-10 ml)         -   1. Couple peptide to Al(OH)₃: 440 μg peptide in 2.2 ml PBS             is added 2.2 ml (17.6 mg) 8 mg/ml Al (OH)₃.         -   2. Mix for 30 min. at 20° C.     -   4. HSP70 (Heat Shock Portein):         -   1. Coupling of peptide to HSP70:             -   Binding Buffer: PBS, 1 M ADP, 1 mM MgCl₂.             -   Stock: 704 μg HSP70 is mixed with 211 μg peptide in 1760                 μl Binding Buffer             -   Incubate for 30 min at 37° C.     -   5. CpG-peptide:         -   1. ODN1826 is mixed to a concentration of 100 μg/ml (2×200             μg+2 ml water)     -   6. B. Pertussis:         -   1. mix 4×10¹⁰ in 2 ml PBS (2×10⁹/dosis)     -   7. dsRNA:         -   1. P(I:C) is mixed to a concentration of 100 μg/ml in 1 ml             PBS.

Adjuvant Mixture Oil Mixture:

-   -   Group 1: 2.2 ml Specol     -   Group 2-7: Mix 21 ml Specol and 9 ml Vitamin E (Oil-in-Oil).         Make 12 aliquots of 2.2 ml each.

Aqueous Solution:

-   -   Group 3: Al(OH)₃:420 μl in 10 tubes (4.2 ml). Add 2×350 μl PBS         to tube 3a and 3b     -   Group 4: HSP70: Add 200 μl to 8 tubes (1600 μl). Add 300 μl PBS         to tube 4a and 4b.     -   Group 5: CpG: Add 400 μl to 6 tubes (2400 μl). Add 200 μl PBS to         tube 5a and 5b.     -   Group 6: B. Pertussis: Add 400 μl to 4 tubes (1600 μl). Add 100         μl PBS to tube 6a and 6b.     -   Group 7: dsRNA pl:C: Add 400 μl to 2 tubes (800 μl).

Mixture

The aqueous solutions (1.8 ml/tube) are added drop by drop during vortexing to 2.2 ml oil mixture. Each tube contains immunization material for 4 chickens.

Immunization Protocol:

-   -   Day 1:1. immunization of 4 chickens×7 groups with 1 ml adjuvant.     -   Day 10: 2. immunization of 4 chickens×7 groups with 1 ml         adjuvant.

The mixtures are vortexed prior to use.

Blood samples are taken prior to each immunization and 14 days after the last immunization.

According to the results of the above experiments the relevant adjuvants components are chosen to be used in the final protocol to generate the antibody library.

Example 5 IgY ELISA Measurements

-   -   1. 1 μg/ml protein per well in 100 μl 10 mM phosphate buffer pH         7.4, containing 0.15 M NaCl (PBS), incubate for 2 h at room temp         and then at 4° C. for 16 h.     -   2. Wash 3 times with PBS containing 0.1% BSA (bovine serum         albumin) and 0.05% Tween 20.     -   3. Saturation with 200 μl PBS containing 2 mg/ml BSA for 3 h at         room temperature.     -   4. Standard curve 0.005 to 1.28 μg/ml, Serum fivefold diluted no         sample.     -   5. Sample diluted in 100 μl PBS containing 0.1% BSA and 0.05%         Tween is dispensed into wells and placed at 4° C. for 16 h.     -   6. Wash 3 times with PBS containing 0.1% BSA and 0.05% Tween 20.     -   7. Add secondary antibody at a ratio of 1/10000 to the wells and         incubate for 2 h at room temperature.     -   8. Wash with PBS containing 0.1% BSA and 0.05% Tween 20.     -   9. OPD Tablets.     -   10. Stop reaction by addition of sulfuric acid.     -   11. Measure absorbance at 450 nm.

Example 6 Antibody Purification

The peptide, protein, or chemical which the customer wants antibodies against is synthesized and coupled to an epoxy bar. Following the coupling the bar is transferred to the library. In the library relevant antibodies bind the antigens. By subsequent transfer to varying pH strength the bound antibodies can be divided into three categories: weak, medium and strong binding. The antigen is bound covalently to the bar while the antibody is linked to the antigen by ion-bonds. The weakest bound antibody is reused in the library.

Example 7 Antibody Isolation from the Egg Yolk

Classical Method with Ammonium Sulphate

-   -   1. Separate egg white and yolk. Wash the yolk with 2 volumes         H₂O.     -   2. Puncture the yolk and dissolve it in 1:10 weight/volume H₂O.     -   3. Freeze and dry the solution.     -   4. Add solid ammonium sulphate to 25% saturation; incubate at         room temperature for 20 min.     -   5. Centrifuge for 30 min at 2500×g.     -   6. Transfer the supernatant to a new glass and add solid         ammonium sulphate to 40% saturation. Incubate at room         temperature for 20 min.     -   7. Centrifuge for 30 min at 2500×g.     -   8. The pellet is redissolved in 1 ml PBS/0.1% NaN₃

Amount of ammonium sulphate (in grams) that has to be added a 1 L solution at 20° C.=553(S₂−S₁)/100−0.3*S₂, wherein S₂=Final concentration of 25%; S₁=Start concentration, fx. 0%-25%:133.25 g/L and 25%-40%:90 g/L

Alternative Method 1 with NaCl

-   -   1. Separate egg white and yolk. Wash the yolk with 2 volumes         H₂O.     -   2. Puncture the yolk and dissolve it in 1:10 weight/volume H₂O.     -   3. Freeze and dry the solution.     -   4. Add 133.25 g solid NaCl to 25% saturation, incubate at room         temperature for 20 min.     -   5. Centrifuge for 30 min at 2500×g.     -   6. Transfer the supernatant to a new glass and add solid NaCl to         40% saturation. Incubate at room temperature for 20 min.     -   7. Centrifuge for 30 min at 2500×g.     -   8. The pellet is redissolved in 1 ml PBS/0.1% NaN₃         Alternative Method 2 with Chloroform     -   1. The egg yolk is separated from the egg white.     -   2. Add 100 mM Sodium Phosphate Buffer pH 7.6 to volume 60 ml and         mix.     -   3. Add 40 ml chloroform and mix to a semi-solid phase.     -   4. Centrifuge for 30 min. at 1500 g.     -   5. Isolate the supernatant.     -   6. PEG-6000 is added to a final concentration of 12% w/v. Mix         until PEG is dissolved.     -   7. Centrifuge for 10 min. at 16.000 g.     -   8. The pellet is dissolved in 100 mM Sodium Phosphate Buffer pH         7.6.     -   9. Sodium azide is added to 0.05%.

Example 8 Isolation of Antigen Specific Antibodies

One gram of cyanogen bromide-activated sepharose 4B (Pharmacia) was swollen according to manufacturers instructions to yield 3.5 ml of resin.

2.5 mg peptide was dissolved in 0.5 M NaCl, 0.1 M NaHCO₃, pH 8.3 and added to the swollen sepharose. The peptide:resin mixture was mixed for 2 hours at room temperature and centrifuged at 40×g for 5 min. The resin was subsequently incubated with blocking buffer (0.2 M Glycine, pH 8.0) at 4° C. for 16 h. The peptide:resin was then poured into a column and washed 5× with 0.5 M NaCl, 0.1 M NaHCO₃, pH 8.3 followed by 5 ml 0.5 M NaCl, 0.1 M ammonium acetate, pH 4.0.

After rinsing the column with 50 ml PBS, 8 ml IgY obtained in Example 3 was mixed with 42 ml PBS and loaded overnight at 4° C. at a flow rate of 30 μl/min. The column was subsequently washed with 50 ml PBS. The antibodies that did not bind to the column were dialyzed for 24 hr against 1 liter of PBS with 2 buffer changes 4° C. Cut off: 3,500. After dialyzation, antibodies can be returned to library to be used for another occasion.

Antigen specific antibodies were eluted from the column with 0.15 M NaCl, 0.2 M glycine, pH 2.2. The eluate was neutralized with 1 M Tris-HCL pH 8.0 and stored at 4° C. with 0.01% NaN₃.

Example 9 Affinity of Antigen Specific Antibodies

To measure the antibody affinity, purified antibody is reloaded on column. Instead of eluting with pH 2.2 a range from pH 8.0 to pH 1.0 is used. Amount of antibody released at a specific pH is measured at 280 nm. The absorbents peak of the pH range indicates its affinity.

Example 10 Optimal Conditions for Shipment and Storage of the Antibodies

Antibodies are very stable under mild denaturating conditions. This makes it possible to ship and store the antibodies in PBS Buffer, pH 7.0 (the antibody structure is preserved) and sodium azide 0.05% (anti-bacterial and anti-fungal) at room temperature for at least 14 days.

Storage at −20° C. is possible for years. The library will be divided into a stock at −20° C. and a stock at 1° C. to avoid damage due to thawing and freezing. Long-term storage of hybridoma cell lines for the generation of monoclonal antibodies is carried out by centrifugation at 4° C. in a solution containing nourishment and DMSO (as cryo protectant). Afterwards the hybridomas are slowly frozen and stored in liquid nitrogen.

Example 11 Monoclonal Antibodies Removal of Bursa of Fabricius

The chickens will be killed by decapitation and the bursas of Fabricius/Bursa fabricii removed.

Bursa fabricii is removed using sterile techniques and transferred to a cell culture dish, containing 10 ml 37° C. medium without serum. Non-bursa tissue is removed. Bursa fabricii is comminute/shredded with a 19 G needle and subsequently with a pipette. The cell suspension is transferred to a sterile centrifuge bottle. The cells are allowed to settle for app. 2 min. The supernatant is transferred to sterile centrifuge bottles.

Fusions

Interspecies hybridomas are made between the antibody producing B-cells of the chicken and a sp2/0 myeloma cell line as follows:

Add 0.3 g 50° C. polyethylene glycol (PEG) to 0.7 ml medium without serum and transfer to a 37° C. water bath. Centrifuge the B-cells at 400 g for 5 min and remove the supernatant. Centrifuge 20 ml myeloma cells at 400 g for 5 min and remove the supernatant. Resuspend the cell pellets in 5 ml medium without serum. The B-cells and the myeloma cells are centrifuged at 400 g for 5 min. Remove the supernatant. Add 0.2 ml PEG to the respective cell pellets and resuspend the pellets carefully. Centrifuge at 400 g for 5 min. Resuspend the respective pellet in 5 ml medium without serum and add 5 ml medium with 20% serum. Centrifuge at 400 g for 5 min. Resuspend the cell pellets in medium containing 20% serum, 1×OPI Oxaloacetat Pyruvat Insulin, 1×AH Azaserin Hypoxanthin.

Isolation of Antibody Producing Cells

The antibodies are displayed on the surface of the hybridoma. Therefore the hybridomas can be isolated as the antibodies are isolated as previously described. When the antibody producing hybridomas are isolated a fast production can be made.

The isolation must be carefully performed. Contamination from other cells cannot be tolerated in the production of monoclonal antibodies. The sonication has to be performed with a lower intensity, to avoid destruction of living cells. When a single cell is isolated the procedure as described in monoclonal antibody production is resumed. The probability of mistaken B-cell isolation is low, but will although be tested in ELISA.

Alternatively the hybridomas can be isolated based on the secernation of the antibodies to the medium. Identification of the antibody producing hybridomas is made by analysis of the supernatant and further subcloning of the cells. After 5-6 subcloning the antibody producing monoclonal cell will be identified and isolated.

Monoclonal Antibody Production

Hybridomas are grown in Sigmas H4409 medium. The cells are divided in to fractions. The first fraction is stored frozen for later use. The second fraction is grown to confluence and antibodies are collected when the antibody production ceases (9 days). It is expected that the antibody production is 175 μg antibody/ml medium in 9 days.

By experience it is known that problems in the production of monoclonal antibodies primarily relate to randomised fusions. Some of the hybridomas grow fast, some slow, some do not grow at all. But if the fusions take place randomly, the probability of presentation of all kinds of peptides will increase by using more cells and more fusions. If a representative mix of hybridomas is achieved, it is possible to isolate one of each type of antibody producing hybridoma. The cells can be isolated as a gathered group of cells producing the same antibody. Later in the growth-phase a natural selection will be made where the fast growing cells will dominate. At this stage it is tested if the antibody production is efficient.

Example 12 Diversity of Antibody Library

10.000 peptides of 15 amino acid residues in length were randomly synthesized and used as the antigen library (Bib). Also 4 control peptides of 15 residues in length were synthesized: C, Ec, Sf-2, Sf-3. All peptides were C-terminally “tagged” with cysteine and coupled to the carrier protein KLH. Afterwards the peptides were mixed to make a 1:12.000 representation of all peptides: 2 mg Bib and 0.2 μg of each control peptide. The mixture was injected to 19 week old Isababcock hybrid chickens, a total of 2 mg peptide-KHL was used. Specol was used as adjuvant at a ratio of 1:1. The chickens were reimmunized (boosted) on day 10 after the first immunization.

The control peptides are of the following sequences:

1. C: CREGPTKGMHTAVQGL 2. Ec: MAPGSTVGTLVANMTC 3. Sf-2: CDKIDSYAQQDLKKGLHLYG 4. Sf-3: CFFAYSDKIDSYAQQD

Test Results:

Prior to immunization blood samples were taken (pre-serum). Date: 22/3, 4/4 and 18/4. The samples were diluted 1:100 and tested by ELISA. A 1:10.000 dilution of secondary antibody-HRP was used. In these tests, each well was pre-coated with 100 ng peptide or peptide library. Controls were performed on wells not precoated with any protein or peptide. For all measurements control measurements were performed. Measurements of blank samples are subtracted the sample measurements. All results have been reproduced. The highest obtained background signal (triple measurements) was subtracted from the ELISA results of the samples. The background signals were registered 18/4. Before this the sample results was lower or equal to the highest background signal.

ELISA Results:

TABLE 1 Induction of immune response in a hen to selected target antigens. The hen was immunized with a large amount and number of different peptides. Control samples were blood samples collected before immunization. The results shown in the table are reproducible. Dato KLH Bib Bib C C Ec Ec Sf-2 Sf-2 Sf-3 Sf-3 22/3 0 0 0 0 0 0 0 0 0 0 0  4/4 0 0 0 0 0 0 0 0 0 0 0 18/4 2.52 1.84 1.90 0.05 0.04 0.04 0.04 0.07 0.07 0.01 0.01

Interpretation of the Results:

It is possible to immunize with 10.000 peptides and still obtain antibodies against a specific peptide. To conclude: it is possible to distribute the antibody production over as many as 10.000 antigens. The high-quantity production of antibodies in a chicken can therefore be exploited to produce small quantities of a single antibody.

Contrary to the general presumptions in the art, it is possible to immunise with large numbers of antigens, here 10,000 different peptides, AND obtaining specific antibodies. It is thus possible to produce a large amount of different antibodies in one animal and by exploiting the ability of the hen to produce large amounts of antibodies which can be collected from the eggs. It is furthermore demonstrated that immunisation with small amounts of antigen is possible without inducing anaphylactic shock in the animal.

Note:

The ELISA measurements can be translated into linear results by the standard curve shown in FIG. 1. The curve is based on a number of measurements on samples of known antibody concentration. The curve does not correspond to the original measurements and therefore it can only be used as an indication. The highest measurement (2.52 for KLH) lies outside the standard curve. This can only be interpreted as high. Bib 1.84 and 1.90 lie on the curve which correspond to an around 1000 ng/ml.

Example 13 Library Antibodies for the Treatment of Diarrhea in Piglets—Protocol I

Diarrhea in piglets is considered as one of the largest contributors (4-7% of all born piglets die of this) to the high mortality in piglets. The purpose of this experiment is to produce antibodies in chickens against pathogens causing diarrhea in piglets:

Clostridia Cocciciosis Colibacillosis (E. Coli) Porcine Epidemic Diarrhoea (PED) Porcine Reproductive and Respiratory Syndrome (PRRS) Rotavirus Transmissible Gastro-Enteritis (TGE) Protocol I:

19 weeks old chickens, Gallus gallus domestica, are immunized with fragments from the pathogens (killing by heat and use all the juice) in a Super Adjuvant mixture.

100 chickens are immunized according to the scheme. Approximately 14 chickens/group. The chickens are kept isolated to ensure proper collecting of eggs.

Experimental Period: 6 Weeks Immunization Scheme:

Group 1 2 3 4 5 6 7 Pathogen Clostridia Cocciciosis Colibacillosis PED PRRS Rotavirus TGE (E. Coli)

Immunization: day 0 Immunization: day 14

Blood samples are drawn from the chickens at day 0, 10, 20, 30. Eggs are collected from day 21. Evaluation of the immune response raised in chickens

The serum is isolated from the chickens, and antibody titers against the specific pathogens determined by ELISA.

Purification of IgY

The specific antibodies are purified from the egg yolks using NaCl-precipitation according to the example above. Hereafter a specific purification of the antibodies is made by immune specific affinity chromatography.

Example 14 Library Antibodies for the Treatment of Diarrhea in Piglets—Protocol II

The antibody content in the sows' milk contributes to the protection of the piglet including both resistance to infection and development of immunological tolerance to harmless environmental antigens. The listed pathogens are common in the environment of the swine farm, and the antibodies can be isolated from milk from the sow. It is important though that the sows have not been protected from this environment as is often the case. The main reason for the high mortality among piglets is the lack of antibodies transferred from the mother through the colostrum. Isolation of antibodies against top 10 diseases causing diarrhea in piglets is performed using standard purification procedures.

Isolation of Peptide/Antigen

The peptides are magnetically coupled and the antibodies are dipped into the peptide mixture. Subsequently the peptides are eluted by their degree of affinity as this correlates with decreasing pH during the different elution steps.

The peptides thus captured are analyzed and synthesized in large quantities after which chickens are immunized with the newly synthesized peptides in larger. In this manner larger volumes of more specific antibodies may be generated and isolated. Furthermore, by analyzing the peptides caught a subtraction method of selecting for mutated pathogens can be employed.

Development of Specific Antibodies in Chicken

19 weeks old chickens, Gallus gallus domestica, are immunized with peptides reacting with specific antibodies in a superadjuvant mixture. Hereby a specific immune response and specific antibodies are formed in the chicken. The IgY antibodies against the pathogen/peptide are purified from the egg yolk as described elsewhere.

Alternatively the antibodies can be isolated from the antibody library by coupling the identified peptides and/or the pathogen of interest. This method is already described.

Application of Antibodies

The pathogens described in this field exert their effect through the gastrointestinal tract. The application of antibodies may trap the antigen/pathogen in the gastrointestinal tract

-   -   thereby hinder the adherence of the pathogen and further         replication. Preferably this could decrease the duration and the         extent of the disease—thereby decrease the high mortality among         piglets.

The antibodies are administered to the piglets in two different ways:

-   -   Coupling of antibodies 1:1 by binding of the Fc portion of two         (or more) antibodies. The first antibody will trap the complex         after binding to the corresponding epitope, hereafter the second         antibody is able to bind another epitope creating a polyclonal         antibody-antigen complex inactivating the pathogen     -   Coupling of antibodies to a non-digestible material as clay or         plastic The antibodies trap/immobilize the pathogen and due to         the non-digestible material they will be transported through the         gastrointestinal tract and out with the feces.

REFERENCES

-   B. T Bennett et al., Review of polyclonal antibody production     procedures in mammals and poultry, ILAR News, 37, 93, 1995. -   J. Kollerup et al., Effect of homogenization and pasteurization on     the allergenicity of bovine milk analysed by a murine anaphylactic     shock model, Clin. Allergy, 17, 5, 449-458, 1987. -   J. Hau et al., Reagin production in mice: effect of subcutaneous and     oral sensitization with untreated bovine milk and homogenized bovine     milk, In Vivo, 3, 271, 1989. 

1.-67. (canceled)
 68. A method for generating a library of randomly generated IgY antibodies for targeting multiple ligands, said library comprising a plurality of antibodies, said method comprising the steps of: a) generating a peptide library by random peptide synthesis, wherein the resulting peptides are randomized at each amino acid residue; b) immunizing each of a plurality of avian organisms of the same or different species with a composition comprising a plurality of different peptides of the library produced in step a); c) isolating antibodies from the yolk of eggs laid by the plurality of immunized avian organisms of step b); and d) pooling said isolated antibodies.
 69. The method of claim 68 further comprising the steps of e) targeting said pool of antibodies with a ligand; and f) isolating a library of antibodies having affinity for said ligand.
 70. The method of claim 68, wherein the ligands are not used for immunization.
 71. The method of claim 68, wherein, in step b), each avian organism is immunized with at least about 100 different peptides.
 72. The method of claim 68, wherein, in step b), a total of from 10 to 100000 avian organisms are immunized.
 73. The method of claim 72, wherein between 600 and 7000 avian organisms are immunized.
 74. The method of claim 68, wherein the avian organism is a bird of the gallinacean type.
 75. A method for isolating from the yolk of eggs laid by a plurality of immunized avian organisms one or more IgY antibodies with affinity for a ligand without prior immunization of said avian organism with said ligand, said method comprising the steps of: a) generating a library of IgY antibodies by the method of claim 68 to yield a pool of IgY antibodies; b) targeting said pool of antibodies with the ligand; and c) isolating from the yolk of eggs laid by a plurality of immunized, avian organisms one or more IgY antibodies with affinity for the ligand without prior immunization of said avian organisms with said ligand.
 76. The method of claim 75, wherein each avian organism is immunized with at least about 100 different peptides.
 77. The method of claim 75, wherein a total of from 10 to 100000 avian organisms are immunized.
 78. The method of claim 77, wherein a total of between 600 and 7000 avian organisms are immunized.
 79. The method of claim 75, wherein the avian organism is a bird of the gallinacean type. 